Enhance CATS-SB

[svkrieger]

What is this change about?

While working on https://github.com/cloudfoundry/cloud_controller_ng/issues/3589 I realised that the cats broker's response to a request trying to fetch a service binding's last operation cannot be configured. Same was true for fetching a service instance's and service binding's data. This was needed to verify the CC's behaviour for different responses of the service broker.

This PR changes/improves the following:

• The behaviour for a fetch service instance can now be controlled with fetch_service_instance

• The behaviour for a fetch service binding can now be controlled with fetch_service_instance

• The behaviour for a fetch service instance last operation can now be controlled with fetch_service_instance_last_operation

• The behaviour for a fetch service binding last operation can now be controlled with fetch_service_binding_last_operation

• Improved error responses in case a service instance or service binding does not exist but the resource or its last operation is being fetched

• Improved overriding the response json with configuration

Please provide contextual information.

While these changes were made to analyse the CC's behaviour, which is described in https://github.com/cloudfoundry/cloud_controller_ng/issues/3589, it will be helpful for enhancing the cats tests itself in the future to have this behaviour verified whenever the cats run.

What version of cf-deployment have you run this cf-acceptance-test change against?

Please check all that apply for this PR:

• [ ] introduces a new test --- Are you sure everyone should be running this test?
• [ ] changes an existing test
• [ ] requires an update to a CATs integration-config

Did you update the README as appropriate for this change?

• [ ] YES
• [ ] N/A

If you are introducing a new acceptance test, what is your rationale for including it CATs rather than your own acceptance test suite?

CATs should validate common operator workflows. CATs is not a regression test suite. CATs is run by every component team to validate their releases before promotion.

How many more (or fewer) seconds of runtime will this change introduce to CATs?

What is the level of urgency for publishing this change?

• [ ] Urgent - unblocks current or future work
• [ ] Slightly Less than Urgent

Tag your pair, your PM, and/or team!

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The committers listed above are authorized under a signed CLA.

• :white_check_mark: login: svkrieger / name: Sven Krieger (24154654f1f7a726f1550d17d6d121ab60190059)