Start using app.commands.execute for all commands called from extension.ts

[robertbrignull]

We want to replace all calls to commands.executeCommand with app.commands.execute so we can take advantage of the new typing. This PR converts the few calls from extension.ts to the new method. This is just a first small PR to test the approach and make sure we're happy.

I've introduced the separation between commands where we are providing the implementation, and commands that are provided for us but we still want to get strong typing.

If we're happy with the groundwork laid by this PR then we should be able to start converting more command usages.

Checklist

• CHANGELOG.md has been updated to incorporate all user visible changes made by this pull request.
• Issues have been created for any UI or other user-facing changes made by this pull request.
• [Maintainers only] If this pull request makes user-facing changes that require documentation changes, open a corresponding docs pull request in the github/codeql repo and add the ready-for-doc-review label there.

[charisk]

Looks reasonable to me!

[koesie10]

Should this perhaps be called AllExtensionCommands or just ExtensionCommands? I believe we're mostly using extension to refer to the extension (like in ExtensionApp), rather than CodeQL (since this can also refer to the CLI).

[robertbrignull]

Thanks @koesie10 and @charisk for the suggestions on naming. Those are both much better ideas.