Let's extend the test-operator so that it picks up which container image should be used for testing. The test-operator will be picking the information about which image should be executed from following sources (the order defines the precedence of the sources as well):

1. CR (Tempest, Tobiko)
2. CM generated by the openstack-operator
3. Environment variables

DoD:

• The test-operator picks up which image should be used for testing from the sources listed above.

PRs:

• https://github.com/openstack-k8s-operators/test-operator/pull/143