Treat transcript content as unicode strings and convert them at any edge
where we encounter them. One decision made here was to not update
edx-val it treats transcripts as byte but is much closer to the actual
files so it makes more sense over there. But within the platform they
are generally passed around as serialized json and so it's much better
for them to be unicode.
EDUCATOR-1335 - This Adds a dedicated app which is responsible for communication with edx-video-pipeline service. It also adds the backend for saving 3rd party transcription service credentials on edx-video-pipline and cache it in edx-val.
