Release Maven 4 mixin alternatives to application parent poms

[barchetta]

Enhancement Description

Helidon currently publishes application parent poms to provide built-in dependency management and maven plugin configuration (https://github.com/helidon-io/helidon/tree/main/applications). This requires using inheritance and adopting projects must use our application pom as their parent. This tight coupling has negatives, and is one reason why we have stand-alone quickstart examples.

In Maven 4 they have introduced mixins (https://github.com/apache/maven/blob/master/src/site/markdown/mixins.md) which provide a mechanism to share common POM configuration across multiple projects without the limitations of traditional inheritance.

We should publish SE and MP mixins for projects that adopt Maven 4.

This requires that we resolve any other issues that might prevent projects from using Maven 4 with Helidon (see helidon-io/helidon-build-tools#1118)

[barchetta]

4.0.0-rc-4 has been released and is the last planned RC. This indicates that the GA release is should be coming soon.

[talios]

@barchetta Please note that Mixins are being released in Apache Maven 4.1.0, not 4.0.0.

But preparation is good.