Trigger alert if no new objects from Package Metadata DB sync for some time

Problem to solve

License Scanning (LS) and Continuous Vulnerability Scanning (CVS) relies on data exported by the Package Metadata DB (PMDB).

Proposal

We should monitor the sync with the PM DB, count new objects, and trigger an alert if we didn't get new objects for some time.

• Trigger an alert if there's no new license info, because this might break LS.
• Trigger an alert if there are no new advisories, because this might break CVS.

For instance, we could trigger an alert if there are no new object for more than 72 hours.