Add code lens for running migrations

[gmcgibbon]

Motivation

Adds code lens to run migrations to specific versions in the terminal. This is convenient because it allows developers to quickly rollback or fast-forward to specific schema versions with a click.

Part of https://github.com/Shopify/ruby-lsp-rails/pull/239

Implementation

Followed the example of the test running controller and test command registration.

Automated Tests

I don't see any tests for the test command, do they exist? Happy to add tests if I have an example to follow.

Manual Tests

Build the extension, install the extension on a Rails app with Ruby LSP + Rails extension setup using https://github.com/Shopify/ruby-lsp-rails/pull/239. Then, navigate to a migration to observe the added code lens.

[github-actions[bot]]

This pull request is being marked as stale because there was no activity in the last 2 months

[andyw8]

(we'll need to move this over to the monorepo)