LSP: Rename modules

[nadavhames]

Given a file called foo.gleam, (module name foo), and lots of other modules that have import foo and also call foo.stuff().

When foo.gleam gets renamed, we can give the user a choice to auto-rename all references and imports.

We may also want to have a rename module code action when on top of a module reference or import, which would need to also rename the file.

[inoas]

Is file renaming possible via the LSP?
If yes, this would be a real boost IMHO.

[GearsDatapacks]

Yep, this is definitely possible

[lpil]

Let's do it!