Dynamically find out git repo of current repo from .git folder

[mchoma]

Sounds hacky, but can be useful to avoid unnecesary configuration. We find this can be nice to have in OS TS when pointing helm chart to testsuite repo itself

Also note, similar code is already available in intersmash https://github.com/Intersmash/intersmash/blob/main/core/src/main/java/org/jboss/intersmash/IntersmashDeploymentsGitHelper.java just it needs to be generalized to be used with any repo, not just intersmash.