Investigate if we really need TypeResolver at all

[Jalle19]

While working on a side project I realized that resolveType() is not called anywhere, so it's pointless to provide a more complex implementation than return null;.

[hungneox]

It's really weird to me, why we even refactory the TypeResolver class but we've never used it before? :-?

[Jalle19]

@hungneox it seems like it's being used in the 1.4.x version of the library, but not in 1.5 and newer which is what we have here.