Add option to disable real-time updates in web UI (#9984)

app/controllers/settings/preferences_controller.rb

app/javascript/mastodon/actions/notifications.js

app/javascript/mastodon/actions/timelines.js

app/javascript/mastodon/compare_id.js

app/javascript/mastodon/components/load_pending.js

app/javascript/mastodon/components/scrollable_list.js

...features/community_timeline/components/column_settings.js

...todon/features/notifications/components/setting_toggle.js

app/javascript/mastodon/features/notifications/index.js

.../mastodon/features/ui/containers/status_list_container.js

app/javascript/mastodon/initial_state.js

app/javascript/mastodon/reducers/notifications.js

app/javascript/mastodon/reducers/settings.js

app/javascript/mastodon/reducers/timelines.js

app/lib/user_settings_decorator.rb

app/models/user.rb

app/serializers/initial_state_serializer.rb

app/views/settings/preferences/appearance/show.html.haml

config/locales/simple_form.en.yml

config/settings.yml