* feat: add possibility of adding WebAuthn security keys to use as 2FA

This adds a basic UI for enabling WebAuthn 2FA. We did a little refactor
to the Settings page for editing the 2FA methods – now it will list the
methods that are available to the user (TOTP and WebAuthn) and from
there they'll be able to add or remove any of them.
Also, it's worth mentioning that for enabling WebAuthn it's required to
have TOTP enabled, so the first time that you go to the 2FA Settings
page, you'll be asked to set it up.
This work was inspired by the one donde by Github in their platform, and
despite it could be approached in different ways, we decided to go with
this one given that we feel that this gives a great UX.

Co-authored-by: Facundo Padula <facundo.padula@cedarcode.com>

* feat: add request for WebAuthn as second factor at login if enabled

This commits adds the feature for using WebAuthn as a second factor for
login when enabled.
If use...

* Fix media attachment enumeration

* Switch media_attachments id to snowflake ids

Co-authored-by: Thibaut Girka <thib@sitedethib.com>

* Add UserNote model

* Add UI for user notes

* Put comment in relationships entity

* Add API to create user notes

* Copy user notes to new account when receiving a Move activity

* Address some of the review remarks

* Replace modal by inline edition

* Please CodeClimate

* Button design changes

* Change design again

* Cancel note edition when pressing Escape

* Fixes

* Tweak design again

* Move “Add note” item, and allow users to add notes to themselves

* Rename UserNote into AccountNote, rename “comment” Relationship attribute to “note”

- Change audio files to not be stripped of metadata
- Automatically extract cover art from audio if it exists
- Add `thumbnail` parameter to `POST /api/v1/media`, `POST /api/v2/media` and `PUT /api/v1/media/:id`
- Add `icon` to represent it in attachments in ActivityPub
- Fix `preview_url` containing URL of missing missing image when there is no thumbnail instead of null
- Fix duration of audio not being displayed on public pages until the file is loaded

This should not be an issue in practice because of the Rails-level uniqueness
check, but local accounts having a NULL domain means the uniqueness constraint
did not apply to them (since no two NULL values are considered equal).

Fixes #13001

There are no obvious ways it could be misused, as the secret is not
really used for anything, but it is best to secure it for the future

Follow-up to #13613

* Fix PostgreSQL load when linking in announcements

Fixes #13245 by caching status lookups

Since statuses are supposed to be known already and we only
need their URLs and a few other things, caching them should
be fine.

Since it's only used by announcements so far, there won't
be much statuses to cache.

* Perform status lookup when saving announcements, not when rendering them

* Change EntityCache#status to fetch URLs instead of looking into the database

* Move announcement link lookup to publishing worker

* Address issues pointed out during review

* Add shortcuts to blacklist a user's e-mail domain in admin UI

* Add option to blacklist resolved MX and IP records for e-mail domains

* Change ActivityPub follower/following collections to not link first page

* Add support for hiding followers and following of remote users

* Switch to using a single `hide_collections` column

* Address code style remarks

Fix #9106

Fix #12587

* Add announcements

Fix #11006

* Add reactions to announcements

* Add admin UI for announcements

* Add unit tests

* Fix issues

- Add `with_dismissed` param to announcements API
- Fix end date not being formatted when time range is given
- Fix announcement delete causing reactions to send streaming updates
- Fix announcements container growing too wide and mascot too small
- Fix `all_day` being settable when no time range is given
- Change text "Update" to "Announcement"

* Fix scheduler unpublishing announcements before they are due

* Fix filter params not being passed to announcements filter

Fixes #12768

Some migrations were overlooked in #12692

Fixes #12690

The `strong_migrations` update from ba2eac88
introduced a check for `change_column_null` specific to Postgres. This rejects
old migrations.

This commit just wraps old migrations with `safety_assured` to bypass this
check. Alternatives would have been to:
- Disable that check entirely (a possibility added in that same
  `strong_migrations` version) for Mastodon, but it makes sense to write new
  migrations without such a strong lock.
- Rewrite the old migrations to do it in a way that do not require an exclusive
  lock. I thought fixing those old migrations for performance wasn't worth the
  pain. Also, if I understand correctly, the next version of
  `strong_migrations` is going to include a helper to do that. We could update
  those migrations at that point.

* Increased max backup size

* partially reverted schema.rb

* Add backend support for bookmarks

Bookmarks behave like favourites, except they aren't shared with other
users and do not have an associated counter.

* Add spec for bookmark endpoints

* Add front-end support for bookmarks

* Introduce OAuth scopes for bookmarks

* Add bookmarks to archive takeout

* Fix migration

* Coding style fixes

* Fix rebase issue

* Update bookmarked_statuses to latest UI changes

* Update bookmark actions to properly reflect status changes in state

* Add bookmarks item to single-column layout

* Make active bookmarks red

* Add ability to add oneself to lists

* Change search results to include oneself when searching through followers

* Mark follow relation as optional in ListAccount

Fix #12087

Fix #12082

* Add voters count to polls

* Add ActivityPub serialization and parsing of voters count

* Add support for voters count in WebUI

* Move incrementation of voters count out of redis lock

* Reword “voters” to “people”

Fix #11952, regression from #11623

Fix #10736

- Change data export to be available for non-functional accounts
- Change non-functional accounts to include redirecting accounts