Refactor Ruby and output channel

[vinistock]

Motivation

I think there are a few opportunities to improve the code quality in our extension, make it easier to test and better prepare to support Shopify/ruby-lsp#1510.

This PR makes some refactors on Ruby and our output channel.

Implementation

I recommend reviewing by commit.

For Ruby, there are basically three changes:

• Started requiring the workspace folder path (preparation for Support using the LSP with multiple projects in the same VS Code instance ruby-lsp#1510)
• Switched to using async file checks everywhere
• Started avoiding a second shell out to Ruby for fetching RUBY_VERSION and YJIT information. The only version manager where this is not possible is shadowenv, which has a different activation mechanism. For shadowenv, we continue doing the same

For the output channel, the changes are:

• Making it a log channel. This works basically like a Rails logger and is much nicer than what we had before. It includes timestamps and log level
• Put it in a constant, since the channel has no dependencies and we want every part of the extension to always reuse the same one

Started putting common functionality in a common.ts file. I will follow up with some more refactors that will likely move more stuff in there and simplify the existing classes.

Automated Tests

Fixed tests where necessary.