Convert mixin-cache-as-bitmap to TS

[SerG-Y]

Description of change

Converted mixin-cache-as-bitmap to TS

Pre-Merge Checklist

• Documentation is changed or added
• Lint process passed (npm run lint)
• Tests passed (npm run test)

[SerG-Y]

Hi guys,
is it okay to cast some variables to any to be able to access some private fields (ex. _render, _tempDisplayObjectParent , _boundsID)?

@bigtimebuddy @ivanpopelyshev @themoonrat

[bigtimebuddy]

Let's try to avoid the any casts. What's better is something like this so that we can maintain the internal properties in once place and we get the correct type.

interface RendererInternals extends Renderer {
  _tempDisplayObjectParent: Container;
}
this.parent = (renderer as RendererInternals)._tempDisplayObjectParent;

[SerG-Y]

@bigtimebuddy it's not possible in this case because typescript doesn't allow to have the same property in one class private and public in another class/interface.
Any thoughts?

[bigtimebuddy]

Then maybe don’t extend.

[ivanpopelyshev]

_tempDisplayObjectParent - just as any it, I'm gonna remove that object in another PR soon.