Create a mockup of summary sections on other pages

[openjck]

We should create mockups of what summary sections might look like on the User Activity and Usage Behavior page. Summaries for multi-population metrics might look like the horizontal bar graphs on the Hardware page. Summaries for single-population charts might just be numbers like:

YAU: ###,###,###

[openjck]

@SuYoungHong Which metrics would we like to be summarized on each page?

[SuYoungHong]

User Activity
	* YAU
		single number
		ex: 900,000,000 clients
	* MAU
		single number
		ex: 295,000,000 clients
	* Daily Usage
		single number
		ex: 4.808 hours per day
	* Latest Version
		single number
		ex: 68 % of clients on FF58
		NOTE: let me know if this is possible, or a PITA since we'll need to pull the % for that week from the data and the latest version (FF58 in the example) from the annotation

Usage Behavior
	* Top Languages
		stacked barchart like hardware report
	* Always on Tracking Protection
		single number
		ex: 0.8%
	* Has Add-on
		single number
		ex: 35%
	* Top Add-ons
		stacked barchart like hardware report

[openjck]

I'm going to remove this from the Release milestone and put it into the M2 milestone because it's not so critical that it needs to block release. But it would be nice to have sooner than later. The M2 milestone will be the priority as soon as the Release milestone is completed. We might even get to some M2 tasks before the official launch.