Quickstarts run on Quarkus main PRs

Goals:

• active checks of Quarkus PR changes with Quickstarts

Impl:

• GH action step in Quarkus main repo
• JVM mode check

Motivation:

• There were several cases when QS got broken after changes in main. This will give early warning before PR gets in.
• Ecosystem CI for QS provides info when things fail in both JVM and Native, the response loop is often quite long and people do not monitor that actively.