Release generator-jhipster v9.0.0-beta.1

[mshima]

Overview of the feature request

I propose to release a new beta based on current main.
I think v9.0.0 final should be released following Spring Boot v4.0.3 next month.

We should focus on migrating blueprints to v9 and fixing blockers in this cycle.

Motivation for or Use Case

Related issues or PR

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