Elimination of JGit or at most as fallback

Just to add some context, long time ago we were using the native git cli. Then we moved to use JGit because Jenkins started to also use JGit, and consequently the git cli was not available on slaves.

There is no silver bullet, that’s why we have to discuss internally.

Food for though: https://wiki.jenkins.io/display/JENKINS/Git+Plugin#GitPlugin-WhyNotJGit