EDUCATOR-1468: Includes the following:
- Translation retrieval process do not use the ranslation endpoint which was previously changed by 3PlayMedia
- Make a single call to retrieve all the translation metadata for a video
- Add 100% test coverage for the modified patch

EDUCATOR-1431 - HEAL process was overwriting transcript statuses as they were combined with transcode statuses. So, separated them out to avoid unnecassary masking of Video's transcript statuses.

- improve logging
- VEDA vedio status updation
- Remove celery task for retriving 3Play translations, accomodate it in heal process
- improve __unicode__ method and add help text
- Add an ability to override developer configs

This implements 3PlayMedia API integration in pipeline.
Other than that it also iuncludes:
-- rename 'Transcript Preferences' to 'Transcript Credentials'.
-- Add migrations.
-- Rename 'Transcription Ready' to 'Transcript Ready'.