RC_* to RINGCENTRAL_*
APP_KEY and APP_SECRET repalced with CLIENT_ID and CLIENT_SECRET to
reflect RingCentral's descriptions
Change RC_SANDBOX to RINGCENTRAL_SERVER and changed its behaviour.
Allows setting the maximum age of voicemails to fetch on the first run.
Other changes:
- Refactor `from` to `age` in function parameters
- Improve README
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
