Change name away from Yarii

[Jared White]

In light of (a) major ecosystem-related advancements related to the Bridgetown project, and (b) the launch of Mozilla's Yari documentation system, I've decided to move away from Yarii branding.

This issue will track the decision making to pick a new brand that is cognizant of both Whitefusion and Bridgetown long-term goals.