[Apicurito] operator is not testable

As a result of this PR [1], apicurito operator is not able to test.

Because of hard-coded image: registry.redhat.io/fuse7-fuse-apicurito:1.5
I cannot change with CR (custom resource) image for apicurito UI so I cannot test CR1 image.

Also, the upgrade scenario is not working at all.

Possibility to change apicurito-ui images with CR is the key functionality of how Apicurito is tested. Without this QE cannot test CR1.

[1] https://github.com/jboss-fuse/apicurio-operators/pull/1