[ Refactoring ] generate accessor driver should work on variable objects

[Ducasse]

as suggested in #18777 by denis

variables first definingClass isInstanceSide

gives all the information.

[jecisc]

There is one problem with this it's for shared variables.
They can be accessed instance or class side.

What Alexis proposed is getting the info from Calypso. If the user is instance side, we generate instance side. If they are class side, we generate class side.

But this info is missing if we just have the variable object.

Now maybe we could say that by default, it would be class side for shared variables if we provide the object and the user can update the #isMeta: variable himself?

[AlexisCnockaert]

So a solution would be to pass the variable object to the driver and let the user handles the shared variables generation right

[jecisc]

When setting a shared variable we can set #isMeta: to true by default and the user can change the value of the parameter

[AlexisCnockaert]

Ok I will take care of it