Define `Settings::BaseController#set_body_classes` so that sub classes
inherit `Settings::BaseController` don't need to define
`#set_body_classes` agein.

* Add setting to not aggregate reblogs

Fixes #9222

* Handle cases where user is nil in add_to_home and add_to_list

* Add hint for setting_aggregate_reblogs option

* Reword setting_aggregate_reblogs label

If an unresolved report for the same target account already exists,
no new notification is generated

* Allow selecting default posting language instead of auto-detect

* Enable default language setting in credentials API

* Fix form saving

* Switch filtered_languages to chosen_languages

* Adjust interface

* Remove unused translations

* Add preference to hide following/followers lists

- Public pages
- ActivityPub collections (does not return pages but does give total)
- REST API (unless it's your own) (does not federate)

Fix #6901

* Add preference

* Add delegation

* Fix issue

* Fix issue

* Add option to reduce motion

* Use HOC to wrap all Motion calls

* fix case-sensitive issue

* Avoid updating too frequently

* Get rid of unnecessary change to _simple_status.html.haml

* Add support for selecting a theme

* Fix codeclimate issues

* Look up site default style if current user is not available due to e.g. not being logged in

* Remove outdated comment in common.js

* Address requested changes in themes PR

* Fix codeclimate issues

* Explicitly check current_account in application controller and only check theme availability if non-nil

* codeclimate

* explicit precedence with &&

* Fix code style in application_controller according to @nightpool's suggestion, use default style in embedded.html.haml

* codeclimate: indentation + return

* Add unfollow modal

* unfollowing someone

* remove unnecessary prop

* add a system_font_ui setting on the server

* Plug the system_font_ui on the front-end

* add EN/FR locales for the new setting

* put Roboto after all other fonts

* remove trailing whitespace so CodeClimate is happy

* fix user_spec.rb

* correctly write user_spect this time

* slightly better way of adding the classes

* add comments to the system-font stack for clarification

* use .system-font for the class instead

* don't use multiple lines for comments

* remove trailing whitespace

* use the classnames module for consistency

* use `mastodon-font-sans-serif` instead of Roboto directly

* Set delete_modal preference to true by default
* Does not show confirmation modal if delete_modal is false
* Add ja translation for preference setting page

* Remove allowed_languages and add filtered_languages

* Use filtered_languages instead of allowed_languages

* Naive approached to timeline filtering

* Convert allowed_languages into a db column

* Allow users to choose languages to see statuses in

* Style list items as two columns

* Add a hint to explain language filtering preference

* Add missing fields group on preferences page

* Clean up settings/preferences controller

* Extract a UserSettingsDecorator

This introduces a new per-user preference called
"Auto-play animated GIFs", which is enabled by default. When a
user disables this setting, gifs in toots become click-to-play.

Previews of animated gifs were changed to display the video play
button so that users can distinguish them from regular images.

This setting also affects account avatars in the detailed account
view, which was changed to use the same hover-to-play mechanism
that is used for animated avatars in timelines.

Fixes #1652

to only those from local users; Add link to "extended information" to
getting started in the UI; Add defaults for posting privacy; Change
how publish button looks depending on posting privacy chosen

with YAML-defined defaults. Add admin page for editing global settings. Add "site_description"
setting that would show as a paragraph on the frontpage