Primarily this is supposed to fix the `git pull` aciton triggered by
webhooks from GitHub. But in addition to that the point is to simplify
that committing wrapper which has far too much in it.
Instead of passing everything as CLI arguments one should make use of
already supported environment variables and the `env` argument to
`subprocess` functions like `run()`. Writing extra logic in the wrapper
only makes it unnecessarily complicated.
By passing both user, email, and the SSH options in `run_shell_command`
we avoid the need to repeat the same boilerplate to provide Git config
and SSH credentials.
Signed-off-by: Jakub Sokołowski <jakub@status.im>