Split up codeQL.restartQueryServer command

[robertbrignull]

Splits up the codeQL.restartQueryServer command into three commands, so we avoid calling each one from more than one code or user-triggered location. This will allow us to differentiate command usages in our telemetry.

The original codeQL.restartQueryServer command is defined in package.json and is available in the command palette. I believe we don't need to add either of the two new versions there, because we don't want them to be accessible to the user.

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.