Support adopting existing radosgw buckets and users

The operator previously assumed it created every user and bucket it managed:
reconciling an existing resource could overwrite its user attributes or wipe its
bucket policy, and deleting a CRD always deleted the underlying RGW object (only
Bucket had retainOnDelete). That made taking over pre-existing radosgw state
unsafe. Make adoption first-class.

- add retainOnDelete to ObjectStoreUser and BucketAccess (dedicated users), so
  deleting the CRD orphans the RGW user instead of deleting it (symmetric with
  Bucket)
- merge bucket policy instead of replacing it: the operator marks its own
  statements with a cephrgwop* Sid and preserves any statement it does not own,
  so adopting a bucket with a hand-written policy keeps it; add Bucket
  managePolicy (default true) to opt out of policy management entirely
- only reconcile user attributes the spec sets: DisplayName when non-empty and
  Suspended is now an optional *bool, so adopting a user does not reset them
- record adoption: ObjectStoreUser/Bucket status.adopted (+ printcolumn) is true
  when the RGW object already existed on first reconcile
- add GetBucketPolicy + MergeBucketPolicy; keyed adoption detection off the
  status identity field so a Pending owner wait does not mislabel it
- regenerate CRDs/deepcopy; add docs/adoption.md and
  config/samples/05-adoption.yaml; cover the merge in policy_test.go

Claude-Session: https://claude.ai/code/session_016CEncETbf8cvy1PhsHfFHM

api/v1alpha1/zz_generated.deepcopy.go

@@ -226,6 +226,11 @@ func (in *BucketSpec) DeepCopyInto(out *BucketSpec) {
 			(*out)[key] = val
 		}
 	}
+	if in.ManagePolicy != nil {
+		in, out := &in.ManagePolicy, &out.ManagePolicy
+		*out = new(bool)
+		**out = **in
+	}
 }
 
 // DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new BucketSpec.
@@ -352,6 +357,11 @@ func (in *ObjectStoreUserSpec) DeepCopyInto(out *ObjectStoreUserSpec) {
 		*out = new(int32)
 		**out = **in
 	}
+	if in.Suspended != nil {
+		in, out := &in.Suspended, &out.Suspended
+		*out = new(bool)
+		**out = **in
+	}
 	if in.Quota != nil {
 		in, out := &in.Quota, &out.Quota
 		*out = new(Quota)