Send transcribe job to Assembly.AI lambda

[cjjenkinson]

When the extracted audio is uploaded to S3 this lambda will be triggered which is responsible for dispatching the transcribe job to the third party Assembly.AI service.

Pre-tasks

• Retrieve trial developer key from Assembly.AI
• Look up create job from documentation (https://docs.assemblyai.com/overview/getting-started)

Lambda Logic

• Create a pre-signed URL that has a one hour expiration time for the audio file extracted from the previous lambda
• Dispatch a new job calling the relevant API endpoint
• Mark video state to transcribing and save transcription job ID to video record