Rework client/server/javascript/java generators

[mshima]

Overview of the feature request

Currently there is some confusion about client and server organization.
Since #30461 javascript generators are simple-application without entity definition, which was moved to client generator.
Java on the other hand has entity definition and support through domain generator.
Server generator has many java related support too.

This proposal is to add (java/javascript)-simple-application generators without entity support.
And move every entity related support to java/javascript generators keeping client/server without technology specific support.

Motivation for or Use Case

Related issues or PR

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[mshima]

Missing tasks:

• move from java to java-simple-application

  • build-tool
  • code-quality
  • graalvm
  • jib
  • open-api-generator

• add javascript/javascript:bootstrap generators.