This adds a `keep_local` column to the `account_statuses_cleanup_policy` table in the database. There is a new checkbox in the preferences for automatic post deletion, and when calculating which statuses to delete there is now a filter for `without_local_scope`.
* Add account statuses cleanup policy model
* Record last inspected toot to delete to speed up successive calls to statuses_to_delete
* Add service to cleanup a given account's statuses within a budget
* Add worker to go through account policies and delete old toots
* Fix last inspected status id logic
All existing statuses older or equal to last inspected status id must be
kept by the current policy. This is an invariant that must be kept so that
resuming deletion from the last inspected status remains sound.
* Add tests
* Refactor scheduler and add tests
* Add user interface
* Add support for discriminating based on boosts/favs
* Add UI support for min_reblogs and min_favs, rework UI
* Address first round of review comments
* Replace Snowflake#id_at_start with with_random parameter
* Add tests
* Add tests for StatusesCleanupController
* Rework settings page
* Adjust load-avoiding mechanisms
* Please CodeClimate
Misty De Meo
Matt Jankowski
Eugen Rochko
Darius Kazemi
Claire