Generate our own QR Codes for the Build->Show QR Code action.

Use our own code (currently javascript in replmgr.js) to generate QR
Codes for the Build->Show QR Code action instead of calling out to the
Google Chart API, which is now deprecated. This also removes a
dependency on an Internet connection (to reach Google).

Change-Id: Ibbdd6be436a7a06eeb1329056c33f72809a8414b