Move static media to static/ and start compiling it.
Until now, static media has lived in djblets/media, which didn't match all of

our other codebases. I've moved all the files to djblets/static and set things

up to compile together our various javascript and CSS files.

Ran build-media.py and verified that everything got compiled correctly.
Used this from Review Board and tested that the dashboard and extensions

  pages still worked and looked correct.