Modify job_configs fields to hold configs, args, and params

Job objects and JobExecution objects need the ability to specify
configs, args, and params for job execution.  This change modifies
the 'job_configs' field to be a dictionary of dictionaries instead of
just a list of config values, like so

job_configs = {"configs": {...}, "args": {...}, "params": {...}}

Change-Id: I5c7a7d1f39f512f0fa52cc6d7a307d771bf8c345
Merge "Modify job_configs fields to hold configs, args, and params"