Add time delay features

[elie222]

Examples:

1. Archive all newsletters in the newsletter group once they're older than a week
2. Label an email as Missing Reply if I haven't replied to them within 24 hours
3. Send a reply email 5 minutes after receiving the email

It may be we implement these in different ways, but listing them all here as there may be a solution that handles all of these use cases together.

[elie222]

They probably have to be handled separately.

1. Archive all newsletters in the newsletter group once they're older than a week
   Possible implementation: cron job that runs twice per day and archives all overdue emails.
   Or: similar but item is queued when email comes in and timer is started

2. Label an email as Missing Reply if I haven't replied to them within 24 hours
   Possible implementation: cron job that runs every 15 mins and applies label if overdue
   Or: pushed to schedule queue and popped when time is up, and then action is applied

3. Send a reply email 5 minutes after receiving the email
   Add delay to Action / ActionItem in db. So if email comes in, processed via webhook, and then scheduled to queue to perform action in 5 mins time.

Two things to note:
There's a concept of delaying a condition check, and also of delaying an action.