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

Conflicts:
- `app/controllers/admin/base_controller.rb`:
  Minor conflict caused by glitch-soc's theming system.
- `app/javascript/mastodon/initial_state.js`:
  Minor conflict caused by glitch-soc making use of max_toot_chars.
- `app/models/form/admin_settings.rb`:
  Minor conflict caused by glitch-soc's theming system.
- `app/models/trends.rb`:
  Minor conflict caused by glitch-soc having more granular
  notification settings for trends.
- `app/views/admin/accounts/index.html.haml`:
  Minor conflict caused by glitch-soc's theming system.
- `app/views/admin/instances/show.html.haml`:
  Minor conflict caused by glitch-soc's theming system.
- `app/views/layouts/application.html.haml`:
  Minor conflict caused by glitch-soc's theming system.
- `app/views/settings/preferences/notifications/show.html.haml`:
  Minor conflict caused by glitch-soc having more granular
  notification settings for trends.
- `config/navigation.rb`:
  Minor conflict caused by glitch-soc having additional
  navigation items for the theming system while upstream
  slightly changed every line.

db/migrate/20220611210335_create_user_roles.rb

@@ -0,0 +1,13 @@
+class CreateUserRoles < ActiveRecord::Migration[6.1]
+  def change
+    create_table :user_roles do |t|
+      t.string :name, null: false, default: ''
+      t.string :color, null: false, default: ''
+      t.integer :position, null: false, default: 0
+      t.bigint :permissions, null: false, default: 0
+      t.boolean :highlighted, null: false, default: false
+
+      t.timestamps
+    end
+  end
+end

db/migrate/20220611212541_add_role_id_to_users.rb

@@ -0,0 +1,8 @@
+class AddRoleIdToUsers < ActiveRecord::Migration[6.1]
+  disable_ddl_transaction!
+
+  def change
+    safety_assured { add_reference :users, :role, foreign_key: { to_table: 'user_roles', on_delete: :nullify }, index: false }
+    add_index :users, :role_id, algorithm: :concurrently, where: 'role_id IS NOT NULL'
+  end
+end