chore(ocm): remove OCM plugin from catalog and overlays (#2059)

OCM was deprecated in RHDH 1.8 (RHDHPLAN-265) and is now being removed
per RHIDP-9181. Deletes the workspace overlay, Package metadata, Plugin
catalog wrapper entity, supported-packages entry, and CODEOWNERS line.

Made-with: Cursor

Author: polasudo

.github/CODEOWNERS

@@ -52,7 +52,6 @@
 /workspaces/lightspeed                                                  @redhat-developer/rhdh-ui @karthikjeeyar @rohitkrai03 @redhat-developer/rhdh-ai
 /workspaces/nexus-repository-manager                                    @redhat-developer/rhdh-ui @debsmita1 @ciiay   @jessicajhee
 /workspaces/npm                                                         @redhat-developer/rhdh-ui @christoph-jerolimov
-/workspaces/ocm                                                         @redhat-developer/rhdh-plugins   @redhat-developer/rhdh-ui
 /workspaces/odo                                                         @rm3l
 /workspaces/orchestrator                                                @batzionb @mareklibra @gciavarrini
 # /workspaces/pagerduty-backend

catalog-entities/extensions/plugins/openshift-cluster-manager.yaml

@@ -32,10 +32,6 @@ extensions/plugins/catalog-backend-module-extensions
 extensions/plugins/extensions
 extensions/plugins/extensions-backend
 
-# deprecated in 1.8 - TODO remove in 1.10 - https://issues.redhat.com/browse/RHIDP-9179
-ocm/plugins/ocm
-ocm/plugins/ocm-backend
-
 quickstart/plugins/quickstart
 
 rbac/plugins/rbac