Create mobile rewards toggle component

[ryanml]

This will be a fixed position sticky toggle that persists at the top as you scroll in the main settings page. It will break out of the settings page container and stay full width.

Pictured as the first item here:

[petemill]

@ryanml before we get too far with this, it looks like we just have a fixed-size mock-up here. Have you discussed with a designer how this looks on the larger android displays?

[ryanml]

@petemill I discussed with @jenn-rhim / @anthonypkeane , there is going to be a maximum content width of 800px for tablet (similar for example to how you have content constraints on chrome://settings). So the look of this component will not deviate much as it appears in the design.