Kogito: Document alternative workflow for native image building and deployment (Mandrel) BAPL-1822

An alternative workflow was proposed to native image creation and deployment.
In such an alternative workflow:

1) does not use our s2i flow (at least not for the full process)
2) does not use the kogito cli
3) does not depend on our operator

instead:

1) users will create a native image locally using the Quarkus builder image and
2) will push the native image to the cluster using `oc` or other similar flow (e.g. what about Kube?)

Thus:

it is necessary to verify one such flow works and update the documentation accordingly