MAJOR chore(v6): neutral prerequisites for fabric.Group rework

[ShaMan123]

This PR brings in a couple of changes.

• Add changes to chooseObjects to render to support the rendering of stacks when an item inside a group is selected
• it caches the objectsToRenderArray so it does not need to get calculated each render
• it uses onObjectAdded, onObjectRemoved to invalidate objectsToRender stack
• adds some extra logic to findTarget in order to recognize controls / targets inside a groups ( not used for now )
• fix the detection of the arrow cursor angle for objects inside groups ( not used for now )
• introduces an utility getTotalAngle
• rename getCenterPoint with getRelativeCenterPoint, while getCenterPoint will now always return canvas coordinates, while getRelativeCenterPoint will behave like the old getCenterPoint, returning the coordinates in the space where the object is.
• renames toLocalPoint into normalizePoint
• deprecates willDrawShadow

[ShaMan123]

ready

[github-actions]

Code Coverage Summary

> fabric@5.1.0 coverage:report
> nyc report --reporter=lcov --reporter=text

-----------|---------|----------|---------|---------|-----------------------------------------------
File       | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s                             
-----------|---------|----------|---------|---------|-----------------------------------------------
All files  |   83.32 |    76.72 |   86.41 |   83.05 |                                               
 fabric.js |   83.32 |    76.72 |   86.41 |   83.05 | ...,29783,29908,29988-30053,30176,30275,30492 
-----------|---------|----------|---------|---------|-----------------------------------------------

[ShaMan123]

@asturur can we merge #7614 ? I am writing lots of code that can be reduced to a call to one of those functions
I don't mind renaming or whatever

I'll wait, you have a lot on your plate

[asturur]

How did you fix the test? i can't see it

[asturur]

ohh ok clear sorry

[asturur]

i m going to rebase the other branch on new master, and fix eventual conflicts.

[asturur]

Ok i will look at transform utils next,
Then i want to separate from that v6! branch the group logic from all the interaction experiments/new logic.

[ShaMan123]

After pulling from origin getTotalAngle is missing the new version and setOnGroup returned
That's the what the was diff showing

[ShaMan123]

tell me when I can push again
I have noticed I forgot to cleanup console.log for collection.mixin

[asturur]

i left setOnGroup in because it doesn't break tests for now ( in master ) leave it in, we can trash it last minute.
for getTotalAngle could i have messed up the merge conflict?

[asturur]

Feel free to push up again, i will try to work myself around the group changes

[ShaMan123]

i left setOnGroup in because it doesn't break tests for now ( in master ) leave it in, we can trash it last minute. for getTotalAngle could i have messed up the merge conflict?

Well it was my bad that I introduced a change there. Pushed now.