Bug 1046815: Update mozharness configs

This almost re-syncs our mozharness config files with the "real" ones in mozharness. The remaining differences are a few references to /tools; I am trying to sort out those differences with Release Engineering, but that may take some time.
Currently, mozharness jobs are much more dynamic than that. For instance, each test job pip installs mozbase before each test run. There are disadvantages to that, for sure, but on the other hand, it ensures that all test jobs are running the same version of these components, and allows Release Engineering to control what is running. 

runtime-binaries.pvt.build.mozilla.org is indeed private, and I cannot access it from my docker image, but the test jobs still run okay with this configuration. (mozharness somehow determines how to redirect...I'm not sure how.)