Switch our pubspec.yamls to using SDK sources so that we can have consistent
source types when we depend on these packages from external packages using SDK
sources.
* update the color and logo for the docs site
* update the color and logo for the docs site
* remove unused file
* removed unused script code
* tweak styles for inherited names
* configs for firebase hosting
* use the implicit FIREBASE_TOKEN
* don't print every command (lowers the chance of printing secret env vars, and for realz only deploy when merging into master
This moves all the bot-related files to `dev/bots`, hiding it from our
home page in github. Also, simplifies the travis setup, though that
doesn't do any difference to the performance sadly.
