Consolidate controller API calls with generic list_resources endpoint

[jlewitt1]

Summary

• Reduces API calls to controller by using new consolidated list_resources endpoint
• Replaces multiple pure K8s proxy calls with single consolidated calls that include server-side filtering and business logic

Changes

New client method

• Added list_resources(resource_type, namespace, label_selector, field_selector, include_events) to ControllerClient

Updated commands/functions to use consolidated endpoint

• kt volumes -A: N calls → 1 call (was looping through namespaces)
• kt list: N+1 calls → 2 calls (revision resources now fetched in batch)
• kt status: Uses resource from service_status() instead of extra API call
• load_configmaps(): Uses list_resources("configmaps")
• check_pod_events_for_errors(): Uses list_resources("events")
• check_replicaset_events_for_errors(): Uses list_resources("replicasets", include_events=True)

Removed deprecated client methods

• list_pvcs() → use list_resources("volumes")
• list_namespaced_replica_set() → use list_resources("replicasets")
• list_config_maps() → use list_resources("configmaps")
• list_events() → use list_resources("events")

[jlewitt1]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• Consolidate controller API calls with generic list_resources endpoint #2079 👈 (View in Graphite)
• Consolidate service status calls into single API request #2076
• Expand controller functionality to support various compute types #1980 : 7 other dependent PRs (#1990 , #1991 , #1992 and 4 others)
• Move all module calls into subproccesses #2070 : 3 other dependent PRs (#2077 , #2080 , #2083 )
• Break up distributed_utils.py #2069
• Rename /servers/http to /serving #2068
• Rename /serving to /provisioning #2067
• main

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