Introduce common controller

[kstrenkova]

To remove duplicate code across the test-operator controllers, this patch introduces a common controller. This change should make fixing controller bugs easier and prepare the test-operator for new resource addition, if it is needed in the future.

Assisted-by: Claude AI

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https://softwarefactory-project.io/zuul/t/rdoproject.org/buildset/adfde4fcd4304119bd34f1850e6865e3

❌ openstack-k8s-operators-content-provider FAILURE in 8m 07s
⚠️ podified-multinode-edpm-deployment-crc-test-operator SKIPPED Skipped due to failed job openstack-k8s-operators-content-provider