docs: Start using Read the Docs (#324)

Highly recommended to look commits one by one. You can see a successful
build here:

https://canonical-ubuntu-pro-for-windows.readthedocs-hosted.com/en/docs/#

UDENG-1551

.github/workflows/automatic-doc-checks.yml

@@ -0,0 +1,16 @@
+name: Main Documentation Checks
+
+on:
+  - push
+  - pull_request
+  - workflow_dispatch
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true  
+
+jobs:
+  documentation-checks:
+    uses: canonical/documentation-workflows/.github/workflows/documentation-checks.yaml@main
+    with:
+      working-directory: './docs'

README.md

@@ -5,6 +5,8 @@
 
 [license-image]: https://img.shields.io/badge/License-GPL3.0-blue.svg
 
+[![Documentation Status](https://readthedocs.com/projects/canonical-ubuntu-pro-for-windows/badge/?version=latest&token=6ab00afc8f04ec33510f3150a8abbae383dfdfc57c1396c899c8f59d46bb0d76)](https://canonical-ubuntu-pro-for-windows.readthedocs-hosted.com/en/latest/?badge=latest)
+
 [codecov-image]: https://codecov.io/gh/canonical/ubuntu-pro-for-windows/branch/master/graph/badge.svg
 [codecov-url]: https://codecov.io/gh/canonical/ubuntu-pro-for-windows
 
@@ -29,6 +31,10 @@ It contains the set of applications to manage Ubuntu WSL instances that allows y
 * Orchestrate instances for Landscape
 * Manages instance states (spin up/down to apply policies/patches).
 
+### Documentation
+
+You can read all about Ubuntu Pro for Windows on [Read the docs](https://canonical-ubuntu-pro-for-windows.readthedocs-hosted.com).
+
 ### System Components
 
 The system consists of the following components:

docs/.gitignore

@@ -0,0 +1,9 @@
+/*env*/
+.sphinx/venv/
+.sphinx/warnings.txt
+.sphinx/.wordlist.dic
+.sphinx/.doctrees/
+_build
+.DS_Store
+__pycache__
+.idea/

docs/.readthedocs.yaml

@@ -0,0 +1,27 @@
+# .readthedocs.yaml
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
+version: 2
+
+# Set the version of Python and other tools you might need
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.11"
+
+# Build documentation in the docs/ directory with Sphinx
+sphinx:
+  builder: dirhtml
+  configuration: docs/conf.py
+  fail_on_warning: true
+
+# If using Sphinx, optionally build your docs in additional formats such as PDF
+formats:
+   - pdf
+
+# Optionally declare the Python requirements required to build your docs
+python:
+   install:
+   - requirements: docs/.sphinx/requirements.txt

docs/.sphinx/_static/custom.css

@@ -0,0 +1,189 @@
+/** Fix the font weight (300 for normal, 400 for slightly bold) **/
+
+div.page, h1, h2, h3, h4, h5, h6, .sidebar-tree .current-page>.reference, button, input, optgroup, select, textarea, th.head {
+    font-weight: 300
+}
+
+.toc-tree li.scroll-current>.reference, dl.glossary dt, dl.simple dt, dl:not([class]) dt {
+    font-weight: 400;
+}
+
+/** Table styling **/
+
+th.head {
+    text-transform: uppercase;
+    font-size: var(--font-size--small);
+}
+
+table.docutils {
+    border: 0;
+    box-shadow: none;
+    width:100%;
+}
+
+table.docutils td, table.docutils th, table.docutils td:last-child, table.docutils th:last-child, table.docutils td:first-child, table.docutils th:first-child {
+    border-right: none;
+    border-left: none;
+}
+
+/* Allow to centre text horizontally in table data cells */
+table.align-center {
+    text-align: center !important;
+}
+
+/** No rounded corners **/
+
+.admonition, code.literal, .sphinx-tabs-tab, .sphinx-tabs-panel, .highlight {
+    border-radius: 0;
+}
+
+/** Admonition styling **/
+
+.admonition {
+    border-top: 1px solid #d9d9d9;
+    border-right: 1px solid #d9d9d9;
+    border-bottom: 1px solid #d9d9d9;
+}
+
+/** Color for the "copy link" symbol next to headings **/
+
+a.headerlink {
+    color: var(--color-brand-primary);
+}
+
+/** Line to the left of the current navigation entry **/
+
+.sidebar-tree li.current-page {
+    border-left: 2px solid var(--color-brand-primary);
+}
+
+/** Some tweaks for issue #16 **/
+
+[role="tablist"] {
+    border-bottom: 1px solid var(--color-sidebar-item-background--hover);
+}
+
+.sphinx-tabs-tab[aria-selected="true"] {
+    border: 0;
+    border-bottom: 2px solid var(--color-brand-primary);
+    background-color: var(--color-sidebar-item-background--current);
+    font-weight:300;
+}
+
+.sphinx-tabs-tab{
+    color: var(--color-brand-primary);
+    font-weight:300;
+}
+
+.sphinx-tabs-panel {
+    border: 0;
+    border-bottom: 1px solid var(--color-sidebar-item-background--hover);
+    background: var(--color-background-primary);
+}
+
+button.sphinx-tabs-tab:hover {
+    background-color: var(--color-sidebar-item-background--hover);
+}
+
+/** Custom classes to fix scrolling in tables by decreasing the
+    font size or breaking certain columns.
+    Specify the classes in the Markdown file with, for example:
+    ```{rst-class} break-col-4 min-width-4-8
+    ```
+**/
+
+table.dec-font-size {
+    font-size: smaller;
+}
+table.break-col-1 td.text-left:first-child {
+    word-break: break-word;
+}
+table.break-col-4 td.text-left:nth-child(4) {
+    word-break: break-word;
+}
+table.min-width-1-15 td.text-left:first-child {
+    min-width: 15em;
+}
+table.min-width-4-8 td.text-left:nth-child(4) {
+    min-width: 8em;
+}
+
+/** Underline for abbreviations **/
+
+abbr[title] {
+    text-decoration: underline solid #cdcdcd;
+}
+
+/** Use the same style for right-details as for left-details **/
+.bottom-of-page .right-details {
+    font-size: var(--font-size--small);
+    display: block;
+}
+
+/** Version switcher */
+button.version_select {
+  color: var(--color-foreground-primary);
+  background-color: var(--color-toc-background);
+  padding: 5px 10px;
+  border: none;
+}
+
+.version_select:hover, .version_select:focus {
+    background-color: var(--color-sidebar-item-background--hover);
+}
+
+.version_dropdown {
+  position: relative;
+  display: inline-block;
+  text-align: right;
+  font-size: var(--sidebar-item-font-size);
+}
+
+.available_versions {
+  display: none;
+  position: absolute;
+  right: 0px;
+  background-color: var(--color-toc-background);
+  box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
+  z-index: 11;
+}
+
+.available_versions a {
+  color: var(--color-foreground-primary);
+  padding: 12px 16px;
+  text-decoration: none;
+  display: block;
+}
+
+.available_versions a:hover {background-color: var(--color-sidebar-item-background--current)}
+
+.show {display:block;}
+
+/** Fix for nested numbered list - the nested list is lettered **/
+ol.arabic ol.arabic {
+  list-style: lower-alpha;
+}
+
+/** Make expandable sections look like links **/
+details summary {
+    color: var(--color-link);
+}
+
+/** Fix the styling of the version box for readthedocs **/
+
+#furo-readthedocs-versions .rst-versions, #furo-readthedocs-versions .rst-current-version, #furo-readthedocs-versions:focus-within .rst-current-version, #furo-readthedocs-versions:hover .rst-current-version  {
+    background: var(--color-sidebar-item-background--hover);
+}
+
+.rst-versions .rst-other-versions dd a {
+    color: var(--color-link);
+}
+
+#furo-readthedocs-versions:focus-within .rst-current-version .fa-book, #furo-readthedocs-versions:hover .rst-current-version .fa-book, .rst-versions .rst-other-versions {
+    color: var(--color-sidebar-link-text);
+}
+
+.rst-versions .rst-current-version {
+    color: var(--color-version-popup);
+    font-weight: bolder;
+}