Adds settings to control the visibility of comment and invited comment features

[ajrbyers]

This PR closes #3097

• Adds two new settings to control visibility of comment and invited comment features
• Adds a new decorator (with tests) that can check if a repository setting is enabled
• Adds logic to the repository_preprint view to block comments when the feature is disabled

Comments block removed:

Manage Reviewers Removed:

Comments Controls Removed:

[ajrbyers]

• Fix conflicts
• Rebase after Fix repository migration conflict #4368 is merged

[mauromsl]

Lovely work

[joemull]

I'm getting conflicting migrations:

CommandError: Conflicting migrations detected; multiple leaf nodes in the migration graph: (0045_historicalrepository_display_public_metrics_and_more, 0045_historicalrepository_enable_comments_and_more in repository).