docs: document rustup

Signed-off-by: MarcoIeni <[email protected]>

service-catalog/rustup/README.md

@@ -0,0 +1,18 @@
+# Rustup
+
+Rustup is the recommended tool for installing Rust.
+It is a command line tool that manages Rust versions and associated tools.
+
+The Infra team maintains the infrastructure for Rustup:
+
+- [rustup](https://github.com/rust-lang/simpleinfra/tree/master/terragrunt/modules/rustup)
+  terragrunt module.
+  An S3 bucket called `rustup-build` for storing the Rustup binaries,
+  distributed through CloudFront CDN at `rustup-builds.rust-lang.org`.
+  The [rust-lang/rustup](https://github.com/rust-lang/rustup)
+  GitHub repository builds and uploads Rustup artifacts
+  to this S3 bucket.
+- [win-rustup-rs](https://github.com/rust-lang/simpleinfra/tree/master/terragrunt/modules/win-rustup-rs)
+  terragrunt module.
+  A Cloudfront distribution of the `/rustup/dist` path of the `static-rust-lang-org` bucket providing convenient short for downloading
+  rustup on Windows.