In JitRegCache.cpp, the lambda predicate were replaced by a pointer to member function because ranges algorithms are able to invoke those.

In ConvertDialog.cpp, the `std::mem_fn` helper was removed because ranges algorithms are able to handle pointers to member functions as predicates.

In BoundingBox.cpp, the lambda predicate was returning the bool element unchanged, so `std::identity` was a better fit.

Crosses off a lingering TODO.

Also amends a few nearby cases where a u32 cast was being repromoted to
size_t.

They were essentially just pass-though methods

Mostly involves moving contents of OGLRender
to OGLGfx and OGLConfig

Otherwise this is an error on gcc/libstdc++, and there are no transitive
includes for this header.

This moves much of the duplicated bounding box code into VideoCommon,
leaving only the specific buffer implementations in each backend.