[Task] Pluggable Discovery In-Place Model Updates

[andrewazores]

Depends on https://github.com/cryostatio/cryostat/issues/937
Parent: https://github.com/cryostatio/cryostat/issues/936

To serve parent 4 and 6, once we have a database of environment and target nodes, we should use the platform capabilities to listen for changes to these nodes and use those notifications to dynamically update the database contents. For example, in OpenShift, if one of our Endpoints objects disappears, then it should be removed from the database. The parent Pod that contained the Endpoints should be checked, and if it has no other child Endpoints, the Pod should also be removed. Then the Pod's parent Deployment(Config) should be checked and removed if it has no other Pod children.

[github-actions]

This PR/issue depends on:

• cryostatio/cryostat#937
  By Dependent Issues (🤖). Happy coding!