Spike: trigger email to user when STT job completes

[tamsingreen]

This Firebase extension is designed to send mail for bulk email providers only, so can we implement our own? We have a dpe@bbcnewslabs.co.uk email set up through AWS Simple Email Service, can we use it with this library?

Timeboxed spike (1 day?) to explore creating a function triggered by a success message from PSTT, get IAM role set up so Firebase can communicate with SES etc.