In this commit, we copy the implementation of the golangci-lint lll
linter which we currently use in our CI flow during the `make lint`
check. This commit copies the code mostly as is (the only exception
being the line which trims white space before checking if a line starts
with "import"), and formats it to fit our codebase guidelines. A test is
also added so that we can be sure that the following commits which
adjust the implementation have the intended results.

The custom linter is put into its own module as this is requied by the
`golangci-lint custom` when building the custom linter binary which
includes the plugin.

This commit introduces the `LLPlugin` type and converts the existing lll
code such that the LLPlugin implements the register.LinterPlugin
interface. This will allow us to plug it into golangci-linter as a
plugin.

This commit adds a feature to our custom lll linter which will ignore
log lines (both single and multi-lined log lines) for the lll linter.

Add this file both to the main LND directory so that devs can use it for
local linter runs and also add it to the `tools` directory so that the
docker environment used to run the linter in CI has access to it. A
custom linter binary can be built via `golangci-lint custom`. This will
pull in and register all the plugins listed in the new config file when
building the new binary. The new binary can then be run using
`custom-gcl run`.

Find and replace all nolint instances refering to the `lll` linter and
replace with `ll` which is the name of our custom version of the `lll`
linter which can be used to ignore log lines during linting.

The next commit will do the configuration of the custom linter and
disable the default one.

It can be disabled via the new `logging.no-commit-hash` config option.