Grafana upgrades changed on-disk provisioning and our alerts (and maybe more?) aren't properly deployed anymore

As @bendon already pointed out a while ago (and maybe even already created an issue for it?), newer PrivateStorageio Grafana installs don't configure our alerting rules from disk properly as they used to in the past.

Somewhere between the last upgrades either of Grafana or its NixOS tooling, the way to provision the Grafana configuration has changed.

This can be reproduced by standing up a local development PrivateStorageio grid - observe how it has no alerting at all.