changing context for queueing transcript

[nully0x]

This issue focuses on reworking how we queue transcripts and changing to GitHub as the source for transcripts.

Actions items:

• [x] create a webhook to check for appropriate source (via tstbtc) for transcripts and save the URL in db
• [x] create a new migration for transcript_url on the transcript table and branch_url on the reviews table

[Extheoisah]

• [x] parse the transcript content gotten from GitHub and create a new transcript to save to db