Automatically request module for non-standard branches.
    
    This is half of fedrepo_req#129.
    
    Whenever a user requests a non-standard branch, we will also submit a request
    for a matching module with matching stream and matching SLs.
    
    In a subsequent changeset, we want to make the admin tool automatically
    populate new module repos with a useful modulemd starter template.
    
    Signed-off-by: Ralph Bean <rbean@redhat.com>