Enhance debugger attachment requests

[st0012]

Motivation

Port and host support closes #1787
Socket path support is required for https://github.com/Shopify/team-ruby-dx/issues/926

Implementation

Automated Tests

Manual Tests

1. Run the extension with a Rails project as the extension development host
2. To test debugSocketPath:
   1. Run the server with RUBY_DEBUG_SOCK_PATH=/tmp/debug-socket-test bundle exec rdbg -O -n -c -- bin/rails s
   2. Check attaching with the vanilla attaching config failed:

          {
              "type": "ruby_lsp",
              "name": "Attach to rdbg server",
              "request": "attach",
          }

   3. Check attaching with debugSocketPath succeeded:

          {
              "type": "ruby_lsp",
              "name": "Attach to rdbg server",
              "request": "attach",
              "debugSocketPath": "/tmp/debug-socket-test"
          }

3. To test debugPort and debugHost:
   1. Run the server with bundle exec rdbg -p 1234 -O -n -c -- bin/rails s
   2. Check attaching with the vanilla attaching config failed:

          {
              "type": "ruby_lsp",
              "name": "Attach to rdbg server",
              "request": "attach",
          }

   3. Check attaching with debugPort succeeded:

          {
              "type": "ruby_lsp",
              "name": "Attach to rdbg server",
              "request": "attach",
              "debugPort": 1234
          }

   4. Check attaching with incorrect debugHost failed:

          {
              "type": "ruby_lsp",
              "name": "Attach to rdbg server",
              "request": "attach",
              "debugPort": 1234,
              "debugHost": "foobar" # should cause `getaddrinfo ENOTFOUND foobar` error
          }

[vinistock]

I just have an ergonomics comment, but it looks good to me

[vinistock]

Can we combine these two into a single URI? I think it makes it even simpler for the user and we can easily split the host and port by using VS Code's URI API:

const uri = vscode.Uri.parse(session.configuration.debugUri)
uri.host
uri.port

[st0012]

I prefer having them separated because:

1. When connecting with a remote console, the usage is rdbg -A host port, not rdbg -A host:port. When specifying with env, it has RUBY_DEBUG_HOST and RUBY_DEBUG_PORT but no RUBY_DEBUG_URI either. So I think having them separated is more consistent with the terminal experience.
2. port is going to be specified a lot more often than host, which means in most cases debugUri would simply be port, like debugUri: 4000. And IMO debugPort: 4000 is a lot less confusing than it.