Minimally restore lstags to fix ATLINFR-3011
So during the cmt clean-up we got rid of PyUtils/bin/lstags which resulted in ATLINFR-3011. With this MR I'm restoring it as discussed therein. It's cleaned up of cmt/svn related stuff and I kept the bare minimum that is needed. Currently packages.txt under WorkDir lists <unknown> for the tag information, which actually doesn't make too much sense for git-era. I anyhow kept the option of printing that in case we choose to do something else in the future.