Configurable lookback window

[glennmatthews]

Environment

• Nautobot version: 1.1.5
• nautobot-circuit-maintenance version: 0.4.1

Proposed Functionality

When running the handle_notifications job, allow the user to optionally specify a lookback window relative to the last previously processed notification, instead of hard-coding this window to 1 day.

Use Case

For cases where an email or group of emails failed, and the parser libraries have now been updated to handle those emails, it would be useful to be able to manually re-run the job with a lookback window of N days so as to re-process those emails.

It might be necessary to manually delete the RawNotification records corresponding to the failed emails so that they get re-processed; another option would be to make the job smart enough to distinguish between "parsed successfully" and "parsing failed" notifications (by checking for the existence of a corresponding ParsedNotification record?) and re-processing the failed emails regardless?