Improve initial documentation

Provide more detailed guidelines based on the info we have in the
wiki at https://wiki.openstack.org/wiki/LoggingStandards#Guidelines

Provide API documentation for the gettextutils module.

Fix up some formatting issues with the contributing page that kept it
from being included in the table of contents.

Add a description to the README.

Other minor section and document title fixes, and remove unused pages.

Change-Id: I1e0a2be2918fe8f5d4194fc5a82b19edb225c1d0
Merge "Improve initial documentation"