Build books the same way we build them for publishing:
Build all three variants of the Install Guides if we check building.
Since we introduce os specific sections, the guide might build for one
variant but not the others.
In case of failure, the variant is shown like:
Building all queued 1 books now...
>>> Build of book install-guide (for Ubuntu) failed (returncode = 1).
Also, generate the xml file for the HA guide and build it.
Add generated file bk-ha-guide.xml to .gitignore
Add parameter -B for building to mvn to silence download progress
Run test.py and validate.py through pep8 and fix any issues