commands: pass settings via __init__

Instead of setting properties on the instantiated command, pass them
via the constructor like normal objects.

Change-Id: I8787499bd2be68565875ffe243c3cf2024b36ae7
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/309324
Reviewed-by: Raman Tenneti <rtenneti@google.com>
Tested-by: Mike Frysinger <vapier@google.com>