Add e2e tests for che-operator/chectl olm installer in Openshift 4.6 and OCP nightly

[flacatus]

Is your task related to a problem? Please describe.

Actually we are not covering chectl tests in OCP 4.6.

Describe the solution you'd like

Create job in openshift ci which launch OCP 4.6 cluster and run our test there.

Describe alternatives you've considered

Additional context

[tolusha]

In the context of the issue we have to review all tests:

• rename action files
• check if nightly tests use the latest templates (not from chectl ones) https://github.com/eclipse/che-operator/blob/master/.ci/cico_minishift_nightly.sh#L79-L113
• add some more tests (minikube operator)?

[flacatus]

@tolusha Yeah, the idea is check the action files name and if nightly tests use latest templates. Also Will be nice to add in the operator nightly minikube tests with operator installer. In the case of chectl we should add the olm tests

Also we should update OCP 4.3 and OCP 4.4 to OCP 4.6 and OCP 4.7(nightly) for chectl and che operator tests

[tolusha]

Finally for che-operator we should have:
nightly tests (olm installer) on:

• OCP 4.5 4.6 4.7

stable update tests (olm installer) on:

• OCP 4.5 4.6 4.7

Finally for chectl we should have:
nightly tests (olm installer) on:

• OCP 4.5 4.6 4.7

[skabashnyuk]

it would be nice to include a ubi-based che-server image in the che-operator testing process.
That image would be available after #18545

[tolusha]

Depends on #16928