Add rename feature

[RobbyCBennett]

Problem(s) this feature will solve

Add the ability to rename an entity

Describe the solution you'd like

Implement the following in userver:
https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_rename

Implementation details:

• Make a internal headless API to refactor rename, pulling out the reference logic from the existing GUI API. The GUI refactor tool and userver should both use these references.