Add documentation for building with S2I on OpenShift

[siamaksade]

The current docs on the website use Dockerfile for building the app image:
https://quarkus.io/guides/kubernetes-guide

There should also be docs on how to use S2I and OpenJDK builder image for building non-native and possibly also native packaging on OpenShift.

[vorburger]

@siamaksade see also #304 for a prior discussion re. S2I building with -Pnative on OpenShift

[siamaksade]

We should probably separate the (1) S2I build on OpenJDK from (1) S2I build for a native binary. This issue is to track (1). Will comment regarding (2) on #304

[vorburger]

We should probably separate the (1) S2I build on OpenJDK from (1) S2I build for a native binary. This issue is to track (1). Will comment regarding (2) on #304

Sounds like a plan! I've updated the title of #304 accordingly (perhaps you'd like to do the same here and update the title of this issue with a "(non-native)" suffix).

[vorburger]

@siamaksade #1353 and quarkusio/quarkusio.github.io#126, based on the new quarkusio/quarkus-quickstarts#81, will provide this documentation.