Enable MLy pipeline

There a request from @kyle.willetts, @patrick-sutton to enable MLy uploads to gracedb, so this ticket is designed to track that work. The sample upload is here:

mock_event.json

Steps on my part are (roughly) to:

1. Make the new pipeline object and store in a migration. Any MLy developer should be able to upload Test events, so uploaders/robots can be defined later.
2. Modify view_logic.py and assign the pipeline an event type.
3. Modify translator.py to parse the json file and then store it in the db.
4. Modify view_utils.py to serialize MLy events into igwn-alerts and API responses.
5. Create a new view template with tables to show web results.

The last step is to add uploaders and robots to push events in production.