* Add messages informing that collections are empty
Adds empty messages to blocked users, domain blocks, favourited statuses, users
that favourited toot, follow requests, followers of given user, user's being
followed by given user, lists, muted users, toots' boosts.
Switched from using ScrollContainer to ScrollableList and/or added empty
message's text.
Fixes#4115
* Update localization files with strings for #4115
* Fix whitespace issues pointed out by codeclimate
* Add default_settings class method to ScopedSettings
ScopedSettings was extended to use value of unscoped setting instead of
only using defaults set in config/settings.yml for selected settings.
This adds possibility for admins to set default values of users' settings,
for example default theme (as requested in #7092).
* Add ability to change an instance default theme
Closes#7092
Jakub Mendyk