feat: add entities to /purge command

[DereC4]

tried to keep as many things in place as possible, and used the entity ID utility functions from the class to map entity to their numeric ID

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[guss-alberto]

This would be a very welcome addition, however this PR doesn't actually do what it says. I have tested this, turns out that's not how the database schema is set up unfortunately, it just throws SQLITE errors if an entity id is provided.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.