Implement BySelector when ResolveResourceBySelector(...) is available in ocm

[frewilhelm]

Description

In https://github.com/open-component-model/ocm-k8s-toolkit/pull/30 the ResourceID only provides the field ByReference to resolve a resource. In theory, it should be possible to resolve the resource BySelector but the implementation is missing in ocm.

When ResolveResourceBySelector(...) is available in ocm, the code in the resource-controller has to be adjusted respectively.

Done Criteria

• ...
• Code has been reviewed by other team members
• Internal technical Documentation created/updated
• New / changed code is documented
• Analysis of existing tests (Unit and Integration)
• Unit Tests created for new code or existing Unit Tests updated
• Integration Test Suite updated (includes deletion of existing unnecessary Integration Test and/or creation of new ones if required)
• Enduser Documentation updated (if applicable)
• Successful demonstration in Review