Merge branch 'main' into glitch-soc/merge-upstream

Conflicts:
- `README.md`:
  Upstream added a link to the roadmap, but we have a completely different README.
  Kept ours.
- `app/models/media_attachment.rb`:
  Upstream upped media attachment limits.
  Updated the default according to upstream's.
- `db/migrate/20180831171112_create_bookmarks.rb`:
  Upstream changed the migration compatibility level.
  Did so too.
- `config/initializers/content_security_policy.rb`:
  Upstream refactored this file but we have a different version.
  Kept our version.
- `app/controllers/settings/preferences_controller.rb`:
  Upstream completely refactored user settings storage, and glitch-soc has a
  different set of settings.
  The file does not directly references individual settings anymore.
  Applied upstream changes.
- `app/lib/user_settings_decorator.rb`:
  Upstream completely refactored user settings storage, and glitch-soc has a
  different set of settings.
  The file got removed entirely.
  Removed it as well.
- `app/models/user.rb`:
  Upstream completely refactored user settings storage, and glitch-soc has a
  different set of settings.
  References to individual settings have been removed from the file.
  Removed them as well.
- `app/views/settings/preferences/appearance/show.html.haml`:
  Upstream completely refactored user settings storage, and glitch-soc has a
  different set of settings.
  Applied upstream's changes and ported ours back.
- `app/views/settings/preferences/notifications/show.html.haml`:
  Upstream completely refactored user settings storage, and glitch-soc has a
  different set of settings.
  Applied upstream's changes and ported ours back.
- `app/views/settings/preferences/other/show.html.haml`:
  Upstream completely refactored user settings storage, and glitch-soc has a
  different set of settings.
  Applied upstream's changes and ported ours back.
- `config/settings.yml`:
  Upstream completely refactored user settings storage, and glitch-soc has a
  different set of settings.
  In particular, upstream removed user-specific and unused settings.
  Did the same in glitch-soc.
- `spec/controllers/application_controller_spec.rb`:
  Conflicts due to glitch-soc's theming system.
  Mostly kept our version, as upstream messed up the tests.

app/javascript/mastodon/locales/en.json

@@ -20,7 +20,7 @@
   "account.blocked": "Blocked",
   "account.browse_more_on_origin_server": "Browse more on the original profile",
   "account.cancel_follow_request": "Withdraw follow request",
-  "account.direct": "Direct message @{name}",
+  "account.direct": "Privately mention @{name}",
   "account.disable_notifications": "Stop notifying me when @{name} posts",
   "account.domain_blocked": "Domain blocked",
   "account.edit_profile": "Edit profile",
@@ -102,7 +102,7 @@
   "column.blocks": "Blocked users",
   "column.bookmarks": "Bookmarks",
   "column.community": "Local timeline",
-  "column.direct": "Direct messages",
+  "column.direct": "Private mentions",
   "column.directory": "Browse profiles",
   "column.domain_blocks": "Blocked domains",
   "column.favourites": "Favourites",
@@ -220,7 +220,7 @@
   "empty_column.blocks": "You haven't blocked any users yet.",
   "empty_column.bookmarked_statuses": "You don't have any bookmarked posts yet. When you bookmark one, it will show up here.",
   "empty_column.community": "The local timeline is empty. Write something publicly to get the ball rolling!",
-  "empty_column.direct": "You don't have any direct messages yet. When you send or receive one, it will show up here.",
+  "empty_column.direct": "You don't have any private mentions yet. When you send or receive one, it will show up here.",
   "empty_column.domain_blocks": "There are no blocked domains yet.",
   "empty_column.explore_statuses": "Nothing is trending right now. Check back later!",
   "empty_column.favourited_statuses": "You don't have any favourite posts yet. When you favourite one, it will show up here.",
@@ -318,7 +318,7 @@
   "keyboard_shortcuts.column": "Focus column",
   "keyboard_shortcuts.compose": "Focus compose textarea",
   "keyboard_shortcuts.description": "Description",
-  "keyboard_shortcuts.direct": "to open direct messages column",
+  "keyboard_shortcuts.direct": "to open private mentions column",
   "keyboard_shortcuts.down": "Move down in the list",
   "keyboard_shortcuts.enter": "Open post",
   "keyboard_shortcuts.favourite": "Favourite post",
@@ -380,7 +380,7 @@
   "navigation_bar.bookmarks": "Bookmarks",
   "navigation_bar.community_timeline": "Local timeline",
   "navigation_bar.compose": "Compose new post",
-  "navigation_bar.direct": "Direct messages",
+  "navigation_bar.direct": "Private mentions",
   "navigation_bar.discover": "Discover",
   "navigation_bar.domain_blocks": "Blocked domains",
   "navigation_bar.edit_profile": "Edit profile",
@@ -562,7 +562,8 @@
   "status.copy": "Copy link to post",
   "status.delete": "Delete",
   "status.detailed_status": "Detailed conversation view",
-  "status.direct": "Direct message @{name}",
+  "status.direct": "Privately mention @{name}",
+  "status.direct_indicator": "Private mention",
   "status.edit": "Edit",
   "status.edited": "Edited {date}",
   "status.edited_x_times": "Edited {count, plural, one {{count} time} other {{count} times}}",