Add spring-boot/graalvm generator

[mshima]

Overview of the feature request

Native is a feature we want to support and generator-jhipster-native was proposed to merge into main generator.
But CI takes too long, so it would increase maintenance/contribution burden.

The proposal is to add spring-boot/graalvm generator, (and java/graalvm if applies) and add 2 test samples.

• defaults with maven and jwt
• defaults with gradle and oauth2

With this 2 test samples we:

• guarantee that the basics will work with native support.

generator-jhipster-native should be used for native support.
So generator-jhipster-native will be greatly simplified and native option will be marked with experimental.

Motivation for or Use Case

Native is a feature we want to support but for each generator-jhipster release, it requires too many generator-jhipster-native change.
Native requires a more restrictive implementation pattern.

Related issues or PR

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[mraible]

I support this feature request. 👍