virttest API: Introduce version module

In order to get useful debug information for virt test,
introduce a module version that is concerned with finding
the current git version, top commit, condensed version
suitable for python setup tools.

Most of the time we're interested in using the results
from the get_pretty_version_info(), as it is complete,
nice for debug logs.

Also, add the RELEASE-VERSION file that the module
creates (might be useful if/when virt test gets packaged)
to .gitignore.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
standalone_test/virt: Add virt test information to test logs

Add complete virt test info to test logs, to help debug
issues with the test suite itself.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>