Tests for validating ServiceMonitor config before update or creation

[leochr]

Add tests for the scenarios from WASdev/websphere-liberty-operator#160 (Openshift Monitoring not working properly if WSLA is created before the basic-auth credential secret)

PR: application-stacks/runtime-component-operator#584

[kabicin]

I've created https://github.ibm.com/websphere/operators/pull/70 which builds on the common repo monitor tests. Since it applies to all operators, OLO PR #494 should be reviewed/merged before the common repo tests PR.