Cleanup around API responses, scheduler config, etc

* Add a list of namespaces to the API index response. This allows tronview/tronctl to guess the namespace of a job/service even if it is not default.
* Change the API index response to include only name/url for jobs/services instead of a full dict with all the details. I will add a GET /jobs and GET /services to replace this in a later branch.
* Change the way daily schedulers are created. Instead of converting them into a more complex configuration string, just create a GeneralScheduler directly from the daily scheduler config
* move some config parsing utils into `tron.config.config_utils` so they can be used by schedule_parse.py and so that config_parse.py is less cluttered.
* Remove `job_run_time` from `ActionRun`. It wasn't being used.
* Remove `tron/utils/groctimespecification.py`. It hasn't been used since 0.5.0