Tag all resources created by CMO e2e tests

The CMO e2e tests create a bunch of resources. These should be cleaned up on a successful run. However:

• Some test failures leave the create resource behind, which have to be cleaned up before a re-run.
• There have been developer reports that even successful runs don't tidy up everything.

In a CI context this is rarely a problem, however running the tests locally can be made quite awkward, especially repeated runs on the same cluster.

We should tag all resources created by the e2e tests with a label (app.kubernetes.io/created-by: cmo-e2e-test).
This will allow easy cleanup by deleting all resources with that label and will allow for checking proper clean-up.

DoD:
All e2e resources get properly tagged.
It is straight forward to ensure that future code changes don't skip adding this tag.