Add Rename action

[AlexeyRaga]

It looks like the LSP server allows refactorings, like rename, can we have them enabled for the VSCode plugin?

[fdncred]

Not unless someone submits a PR to do it. It would be nice to have though.

[AlexeyRaga]

Challenge accepted! ;)

[AlexeyRaga]

Done @fdncred , the PR is up.