feat: add migration to convert from ngOnDestroy to DestroyRef

[michaelbe812]

DRAFT

Draft for a migration schematic to migrate from ngOnDestroy lifecycle hook to DestroyRef.

Please bare with me - I have not written many schematics for now :)

todos

• tests
• docs

Feedback wanted

I would like to know if you generally like the idea.

Also I would like to know which style you would prefer:

// option 1 (currently implemented this way in the schematic)
export class SomeComponent {
  readonly #destroy = inject(DestroyRef).onDestroy(() => {
    // whatever was before in ngOnDestroy
  });
}

// option 2 
export class SomeComponent {
  readonly #destroyRef = inject(DestroyRef)
  
  constructor(){
   this.#destroyRef.onDestroy(() => {
    // whatever was before in ngOnDestroy
  });
}

}

Anything else I should consider?

[michaelbe812]

@eneajaho
just asking for general feedback:
Would you like to see this kind of migration in ngxtension?
If yes, what general style should the migration follow (see pr description)

looking forward :)