Use pretty json strings for git content
    
    This has 2 advantages:
    1. it makes the requests human readable in general, including
    seeing what did actually change from one commit to the next
    2. it makes objects smalller as the diff will include only the
    stuff surrounding the changed data, not the whole object every time.
    
    Signed-off-by: Simo Sorce <simo@redhat.com>