Spyglass will soon have its plugins separated from its main repo. Many
other OpenStack repositories that utilize plugins have implemented
Python Build Reasonableness to manage their entry points for plugins.
As Spyglass will be managing plugins, it makes sense to stay uniform
with other projects and implement PBR.
Implements PBR using setup.py and setup.cfg files.
Changes README to correct file extension.
Freezes PIP requirements file.
Moves YAPF configuration into setup.cfg file.
Change-Id: I48ac5aeb3e544d3da7ce25bd9b827d8fd9c4e108