We still fetch voicemails from RingCentral every 60 seconds, but now we
check for missing transcriptions every 15 seconds, and poll the database
for voicemails that are ready to be ticketized every second.
Other changes:
- Move Stored(Voicemail|Recording) interfaces into knex/types/tables
module for reduced boilerplate.
- Change updateStoredVoicemail to take Partial<StoredVoicemail>,
allowing to only update only some columns
