Add new type of scope that is independ of the scope stack

[escamoteur]

It seems that many people use scopes mainly to be able to dispose of a whole bunch of objects with one call and that the shadowing feature of the scope stack isn't the most important to them.
With the addition of dropScope() we already started the ability to access a scope independent of the stack position.

Also, I was asked what to do if you want a scope for each entry of a tab in a tabview, that would be more or less parallel and not fit the stack structure of current scopes.

This is currently just a reminder on this topic but feel free to add your ideas how a future version of get_it should handle scopes

[kodhi-tech-lead]

Keeping the scope stack hierarchical and then adding groups where groups are non-hierarchical and each scope layer can contain multiple groups would be neat.