add bash8 tool (like pep8, but way hackier)

unlike our python code, we have no automatic style checking for
bash. For the most part, it's not a big deal, but errant whitespace
or incorrect indenting is sometimes annoying to have to -1 people's
patches for. Instead of constantly picking it up in manual review
maybe we can do better.

This is an uber hacky script which could be used to do just that.

   ./tools/bash8.py file1 file2 file3 ...

And it will show issues found with the files at hand. Lightly
tested in the existing devstack tree, it exposes a few issues that
we might want to think about.

This should be python 3 compatible, and includes argparse to provide
a basic '-h' support to explain how the command should be run.

Change-Id: I5009fa5852595c2953a548e430e5e1ce06ae94e0
Merge "add bash8 tool (like pep8, but way hackier)"