Add responsive panels to the single-column layout (#10820)

* Add responsive panels to the single-column layout

* Fixes

* Fix not being able to save the preference

* Fix code style issues

* Set max-height on the compose textarea and add a link to relationship manager

config/locales/simple_form.en.yml

@@ -26,6 +26,7 @@ en:
         password: Use at least 8 characters
         phrase: Will be matched regardless of casing in text or content warning of a toot
         scopes: Which APIs the application will be allowed to access. If you select a top-level scope, you don't need to select individual ones.
+        setting_advanced_layout: The advanced UI consists of multiple customizable columns
         setting_aggregate_reblogs: Do not show new boosts for toots that have been recently boosted (only affects newly-received boosts)
         setting_default_language: The language of your toots can be detected automatically, but it's not always accurate
         setting_display_media_default: Hide media marked as sensitive
@@ -90,6 +91,7 @@ en:
         otp_attempt: Two-factor code
         password: Password
         phrase: Keyword or phrase
+        setting_advanced_layout: Enable advanced web interface
         setting_aggregate_reblogs: Group boosts in timelines
         setting_auto_play_gif: Auto-play animated GIFs
         setting_boost_modal: Show confirmation dialog before boosting

config/settings.yml

@@ -31,6 +31,7 @@ defaults: &defaults
   noindex: false
   theme: 'default'
   aggregate_reblogs: true
+  advanced_layout: true
   notification_emails:
     follow: false
     reblog: false