fix: Application and Aggregator generic alert rules

[MichaelThamm]

Summary

Blocked by this PR:

• fix: Typing in the rules and cos_tool modules cos-lib#189
  • Removes the need for copy.deepcopy in our lib.

This PR solves the dicsussion in this PR:

• feat: Replace the requirer's rule interface with a rules object #376 (comment)

and most of the logic was ripped from this PR into the Prometheus Remote Write lib:

• feat(charm lib)!: duplicate host metrics missing alert for collectors thru RemoteWriteConsumer prometheus-k8s-operator#748

I update the documentation for generic rules:

Release prep

I have updated the CHANGELOG so that we can release this version and bumped the version to 0.2.0.