Review Leases usage and privileges

### Requirement

We should only limit the access to the same operator namespace and remove the check of the presence of a Lease as a mean to verify if a resource has to be reconciled by another operator.

NOTE: this has to be developed once we drop the support of the `master` trait.

No files, tests, or entry points are named; start by locating Lease privilege checks and the reconciliation decision in the Go operator code. Confirm the master trait dependency first, then verify that access is limited to the same operator namespace and that Lease presence is no longer used to decide whether another operator should reconcile a resource.

Written by the indexing model from the issue text.