I would like to perform an automatic "git push" and "git commit" to remote repositories.
Why automatic? What's wrong with putting git push and git commit (probably in reverse order) inside of your pipelines step?
Can you explain a bit more what you're trying to achieve here, Andres?
You can configure HTTP or SSH access via secure environment variables in Pipelines to push changes back to Bitbucket or another Git repository. (We're working on making the SSH config better as #12891.) Is that what you're after?