RFC: Reimplement GooList as a subtype of std::vector

This reimplements GooList as a subtype of std::vector<void *> to facilitate porting the various places where GooList is used to STL containers. After this change, this can happen mechanically by replacing all of the GooList-specific API by their implementations at the call sites and cleaning up until at some point no more GooList-specific API is left and the type can be removed.

This of course keeps the normally inefficient pattern of storing pointer to objects instead of objects inside these containers which however can then be refactoring in a separate step building on top this and as a pure optimization.