Evaluate the performance benefit of `Type::closureToPHP` and `closureToMongo`

[GromNaN]

Both methods exist since the beginning of the project. Only closureToPHP is actually used to generate code in HydratorFactory (documented by #2855).

They add complexity when implementing a new type (see #2868), so types use the ClosureToPHP trait.

Task:

• benchmark performance of removing this methods and always call the type class
• find refactoring optimization
• maybe deprecate this methods