Summary:
Add data pipeline, detector, and tests for metadata PVC. Currently checks to see if the PVC is stucking Pending mode because StorageClass doesn't exist.
Another option we had for this particular check was to look at events and regex match the occurring event, or check the reason. I found my chosen option easier to evaluate and more stable, but open to suggestions.

Only checks metadata pvc if etcd is not used.

Test Plan: Added tests for logic, test on skaffold by forcing a broken pvc

Reviewers: michelle, vihang, zasgar

Reviewed By: michelle

JIRA Issues: PP-2957

Differential Revision: https://phab.corp.pixielabs.ai/D9606

GitOrigin-RevId: 6399f3c02d8dea2c04087907e6d7a29d9133b7e4