[Docs] Expose timeout options for leader election at the AMQ Broker Operator level

The AMQ Broker Operator is based on the operator-sdk that support leader election.

A timeout on renew a lease == loosing the lease this lead to a restart of the AMQ Broker Operator pod.

Exposing timeout options for leader election at the AMQ Broker Operator level will allow to avoid lot of restarts:

spec:
containers:

• args:
• --metrics-addr=0.0.0.0:8080
• --enable-leader-election
• --leader-lease-duration=60
• --leader-renew-deadline=40
• --leader-retry-period=5