Add E2E tests for restore + backup safety

[jsilvela]

We are adding logic to the operator to:

• avoid having a cluster back up into the same location it restored from
• avoid having a cluster back up into a location already used by another

See issues #61 and #62
Our existing E2E suite covers backup and recovery separately, but not "restored cluster has a backup spec".

Scenarios:

• We have cluster A. We create a cluster B to restore from A, but the YAML for B specifies the same barman object as A. --> FAIL
• We have cluster A. Create cluster B which recovers from A and uses a new location for Backup. Create cluster C which recovers from B and uses A's bucket as a Backup location --> FAIL
• We have cluster A. Create cluster B which recovers from A and back-up's into X. Get B to come up properly and perhaps force some WAL writing. Create cluster C from A, and back up into X too. --> FAIL
• We have cluster A. Create cluster B which backs up to new location X --> AOK

[danishedb]

Added one more scenario where we are verifying cluster creation with same destination path in two different namespace.
We have cluster A. Create cluster B which backs up to new location X --> AOK Didnot added this test cause it is covered already within tests.