[Request] Makefile sample applications should use cryostatio/test-applications

### Describe the feature

See also #485 , https://github.com/cryostatio/test-applications/issues/7

Maybe it is time to remove the sample app targets from the Makefile, and use the hypothetical test-applications manifests above. Or, if the Makefile targets are kept, then they should be updated to use the test-applications images published to `quay.io/redhat-java-monitoring`.

### Anything other information?

_No response_

Start by reading the sample application targets in the Makefile and then review issue #485 and cryostatio/test-applications issue #7. Determine whether those targets should be removed or changed to use the referenced manifests and published images; done means the chosen approach is reflected consistently in the Makefile.

Written by the indexing model from the issue text.