Center the Focused Channel

[athomasmoz]

Why/User Benefit/User Problem

As a user, I want the channel I'm looking at to be in the center of the screen, so it's obvious what's selected and I can easily see what's above & below

Acceptance Criteria (how do I know when I’m done?)

1. When a channel is focused, it is vertically centered on the screen All vertically centered panels will have a 116dp padding to the top of the screen.
2. If the channel is too close to the top of the screen to be centered vertically, the screen respects the padding at the top of the page
3. If the channel is too close to the bottom of the screen to be centered vertically, the screen respects the padding at the bottom of the page