Turns out playback controls wouldn't actually work because the view
would detach but not the actual fragment, resulting in onCreateView
never being called and the entire system falling apart. This fixes
it by just giving PlaybackLayout the viewmodel instance it needs.
I'll need to release a hotfix for this issue since this is really
easy the trigger and really hard to fix unless you know why it
occurs. Android lifecycles suck so much.
Completely refactor PlaybackBarLayout into PlaybackLayout, which now
not only handles the bar behavior but also allows for one to slide
up the bar layout into the full playback layout. This was largely
adapted from umano's AndroidSlidingUpPanel, albeit heavily minified
and mixed with the previous window inset tricks of the previous layout.
There are still some tweaks to be made, but this implementation seems
to be really good.
