Use typesafety within the generator

[Tcharl]

Overview of the feature request

Now that most of the generator is in typescript, type safety can be ensured removing all the any and enforcing attributes types (i.e. let myVar: string), function parameter types, and function return types.

Motivation for or Use Case

Type safety helps to avoid some mistakes, but also helps new jhipster contributors (and occasional contributors like me) to better understand how the generator is architectured: in the end, it speeds up the delivery of new features due to a better developper experience.

Related issues or PR

#26111
#26110
#26096

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[mshima]

I don’t understand the proposal.

[Tcharl]

Just to historize the work on making the generator more typescript friendly sir ;-)

[Tcharl]

@DanielFran I'll leave the bounty to anyone else willing to contribute to the overall rework