add vscoq language server

[gares]

This PR adds the language server for VSCoq2 to the platform (only the dev pick)

Fix #347

[gares]

@MSoegtropIMC can we get this merged soon?
It could help to get windows ci working for vscoq2 (we want to use the platform scripts for that)

[MSoegtropIMC]

I plan to finish the Coq Platform release next week - I didn't plan to merge new stuff before.

[gares]

Ok

[catalin-hritcu]

Has there been any progress on this?

We're considering recommending the Coq platform binary to the students of a course that has just started this week, but most students also need to use VsCoq 2(?) with it. Would distributing custom Coq platform binaries that include this PR be the only way we can do this? Or do you have any easier way you can recommend? Sorry if these are naive questions, but I'm new to the Coq platform :)

[catalin-hritcu]

Discovered that VsCoq Legacy works fine with the latest released Coq platform binary, so we're going to recommend using that.

[MSoegtropIMC]

Yes. And sorry for the delays - we had a lot of technical issues with the 8.19 release. It will most likely be added to 8.20.

[catalin-hritcu]

Somewhat offtopic, but one thing I noticed is that VsCoq 2 also seems to depend on ocaml-lsp-server and ocamlformat, even if these dependencies don't seem to be documented. Will the 8.20 release of the platform binary also provide these dependencies?

[MSoegtropIMC]

Please change the issue title to "Add all packages required by VSCoq 2" and list the packages you know of in the issue description. This should be the safest way to ensure that this works.

I will already add a note to the relase process docs to test VSCoq 2 from 8.20 on.