[IMPL] add lsp server

[Doomsk]

Add LSP server

[Doomsk]

I'm working on a Rust version of the LSP server, which should be fast and good enough to handle the project's needs.

The version 1 plan is to cover:

• syntax highlighting
• code correctness checks
• simple completion
• go to definition
• hover
• rename

Then it's a matter of connecting with the LSP client for different IDE/editors and be happy.
@Tamicktom what do you think of having folders for each of the IDE/editors on the client side? We may want to refactor the repository organization as well.

[Tamicktom]

OK, that's actually a good ideia.