* Record account suspend/silence time and keep track of domain blocks

* Also unblock users who were suspended/silenced before dates were recorded

* Add tests

* Keep track of suspending date for users suspended through the CLI

* Show accurate number of accounts that would be affected by unsuspending an instance

* Change migration to set silenced_at and suspended_at

* Revert "Also unblock users who were suspended/silenced before dates were recorded"

This reverts commit a015c65d2d.

* Switch from using suspended and silenced to suspended_at and silenced_at

* Add post-deployment migration script to remove `suspended` and `silenced` columns

* Use Account#silence! and Account#suspend! instead of updating the underlying property

* Add silenced_at and suspended_at migration to post-migration

* Change account fabricator to translate suspended and silenced attributes

* Minor fixes

* Make unblocking domains always retroactive

* Allow domain blocks to reject media without silencing or suspending

* Fix typo

* Hide 'Reject media' button when superfluous, instead of disabling it

* Properly hide 'reject media' checkbox on page load if needed

This may happen when resubmitting the domain block form after an error.

* Don't ask whether undoing a media-only block should be retroactive

* Rename :media_only block to :noop

* Display :noop block as None in frontend, allow blocks that do nothing

* Remove 'coding' line auto-added by emacs

* Add spec for unblock domain service

* Refactor UnblockDomainService

* Set domain_block by before_action

* Cast value with ActiveRecord::Type

* Batch update

Create MediaAttachment but without actual file download when domain is blocked with reject_media set to true
Clean up old media files when creating a new domain block with reject_media set to true
Return remote_url in media attachments API if local file is not present
Undo domain block action in admin UI
Ability to enable reject_media from admin UI