Support jib "container.entrypoint" configuration parameter

[michael-schnell]

Description

There should be support for the container.entrypoint configuration parameter of jib.

Beyond the simple parameter support, it would be nice to have a way to re-use the standard Quarkus entry point as a variable.

Example:
quarkus.jib.container.entrypoint=/foo/bar/wait.sh && ${quarkus.entrypoint}

This way, we do not have to create the Quarkus entry point manually.

Why?

It is often necessary to do some other stuff before the Quarkus app should start. An example could be some kind of "wait" script or utility that allows the Quarkus app to wait for a database container to be available before the app is actually started. Currently this is not possible when using jib.

Links

This feature is related to the feature #8936 (Support jib "extra directories" feature)

[quarkusbot]

/cc @geoand

[geoand]

#10071 implements this feature.