Auto merge of #100863 - ehuss:sunset-rls, r=Mark-Simulacrum

Sunset RLS

This removes RLS per the plan outlined in https://blog.rust-lang.org/2022/07/01/RLS-deprecation.html. This replaces the `rls` executable with a small program which will display an alert telling the user that RLS is no longer available.

An overview of the changes here:
* Removes the rls submodule and replaces it with a small stub program.
* `rls` is removed from `./x.py install`. I do not think users running `install` will need the stub.
* `rls` is removed from `./x.py test`, it doesn't have any tests.

Other things of note:
* I kept `DIST_REQUIRE_ALL_TOOLS` even though it is no longer needed, with the thought that it could be useful in the feature. However, I could remove it if desired.
* I kept `extra_deps` in `tool_extended` (which allows tools to depend on other things), even though it is no longer needed. This can also be removed if desired.
* ~~This keeps RLS in the macOS `pkg` installer and the Windows `msi` installer. I kinda lean towards removing it from those, but I'm not sure?~~ RLS has been removed from pkg and msi.
* This does not remove the analysis component. It is not clear if we should keep this or not. RLS was the primary user, but I think there are a few users that have made tools around it.
* There will be several followup steps after this PR:
    * Updating the toolstate repo to remove RLS.
    * Updating documentation, such as rustc-dev-guide, to remove references to RLS.

The alert looks like this in VSCode:

<img width="989" alt="image" src="https://user-images.githubusercontent.com/43198/185817530-930c5842-24b5-4162-a213-016a25810955.png">

In Sublime it looks similar.

I would appreciate if others could help test with other editors such as vim or Emacs.