Added bookmarks

• Added:
- bookmarks for GabPRO members only
- migration for creation of StatusBookmarks
- all necessary routes, controllers
- redux for adding, removing, fetching and displaying bookmarks
- bookmark icon
- doorkeeper scopes
- backend and frontend support

Bookmarks behave like likes/favorites, except they aren't shared with other users and do not have an associated counter.

https://github.com/tootsuite/mastodon/commit/dfea7368c934f600bd0b6b93b4a6c008a4e265b0

config/locales/doorkeeper.en.yml

@@ -119,6 +119,7 @@ en:
       read: read all your account's data
       read:accounts: see accounts information
       read:blocks: see your blocks
+      read:bookmarks: see your bookmarks
       read:favourites: see your favorites
       read:filters: see your filters
       read:follows: see your follows
@@ -131,6 +132,7 @@ en:
       write: modify all your account's data
       write:accounts: modify your profile
       write:blocks: block accounts and domains
+      write:bookmarks: bookmark statuses
       write:favourites: favorite statuses
       write:filters: create filters
       write:follows: follow people