markerb is dead and isn't compatible with rails 6 anymore. Removing it
means adding separate templates for text and html, this sadly means some
code duplication, but also luckily the templates aren't that
complicated, so the duplication is also very minimal.
Add Sidetiq webview to the Sidekiq monitoring panel
Add rake task maintenance:queue_users_for_removal
This basically just triggers an immediate run of the normal maintenance remove old users functionality that is normally (if enabled) scheduled to run once a day via sidetiq
Add extra safety when checking for user removal due to inactivity.
Now also user.last_seen will also be checked to make sure a user will not be removed in the event that the Devise rememember me login functionality has stopped the users remove_after timestamp from being removed.
Add initializer for maintenance job.
Add warning about mail being disabled if remove_old_users maintenance is enabled.
