GHSA-mw9r-p8xp-wx96

### Impact

Having the Topic and User operators to watch different namespaces than the one where the Kafka cluster is deployed, is a fully documented feature.

When the `watchedNamespace` field is used within the Topic or User operator (as part of the `Kafka.spec.entityOperator` field), the Cluster Operator creates a Role granting full CRUD on Secrets into the specified namespace. It also creates a RoleBinding to bind such Role to the entity operator ServiceAccount within the namespace where the Kafka cluster runs.

An attacker can craft a Kafka custom resource (in an attacker's namespace) with the `watchedNamespace` field set to a target namespace and then they can mint a token for the ServiceAccount (in the attacker's namespace) to read/write Secrets in that target. This is valid with any target namespace for which the Cluster Operator has the rights (regardless the value of the `STRIMZI_NAMESPACE` environment variable). The at-risk target namespaces are the namespaces which the user has given permissions to the Cluster Operator for, by creating related RoleBinding(s).

### Patches

The issue is fixed in Strimzi 1.0.1 and 1.1.0 by adding a control to enable the watched namespace feature through a dedicated environment variable within the Cluster Operator deployment. The watched namespaces feature is disabled by default.

### Workarounds

A possible workaround for this issue is about using a policy agent like Kyverno or OPA to prevent the usage of the `watchedNamespace` at configuration level within the `Kafka` custom resource.