Mastodon account integration

Been missing a news feed ever since Elon killed Twitter? Join the Fediverse instead! Mastodon is a federated social microblogging infrastructure that works just like Twitter did, and is now just as integrated into SailfishOS as that ever was, and maybe even a little bit moreso.

• Add your Mastodon account from the Settings app, in Accounts>New. Just tell it your home server and log in!
• Browse your feed on the Events view just like the old days.
• Built-in doomscrolling limit!
• Bring up the interaction menu with a long press on a post: Favourite or Re-blog a post instantly, or share the post with another app.
• Share your photos, videos or notes straight to Mastodon.
• Get notifications when something interesting happens!
• Tap on a post to open it in a browser to post a reply, view others' replies and the rest. It should be possible for any Mastodon app to take that over too.

This is really a beta, so please report any bugs. I'll publish the source eventually, but there's a lot to separate and integrate with the existing SailfishOS social modules first. I hope one day it'll get bundled with SailfishOS itself, because we do miss that feed.

NOTE: If you install this manually with rpm, there's a dependency from the Sailfish repos you'll need to install too: eventsview-extensions. If you add the repo or use zypper then that should get handled for you.