This adds the codeQL.model.packName setting, which allows users to specify the name of the CodeQL model pack. Like the codeQL.model.packLocation setting added in #3539, this supports variable substitutions. After the variable substitution has been performed, we'll try to "sanitize" the name to make it valid. The default value is ${owner}/${name}-${language} which matches the previous behavior.

My plan is to add the CHANGELOG entry when all three settings have been added, rather than for each one individually.

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.