Merge appengine application into dart_ci repository

We are merging the dart.googlesource dart_ci repository, which
contains the new result feed, with the GitHub dart-lang/dart_ci
repository, which contains the old appengine application with
a result feed, approvals feed, and log viewer.

Change-Id: Ieda76fafb6237bd739750f342bf0db9adaaf10ba
tree: 87248d88c566dcfd380a552e763bab39d11d0599
  1. appengine/
  2. functions/
  3. results_feed/
  4. .firebaserc
  5. .gitignore
  6. firebase.json