Merge: modelbuilder_base: Refactor the signature of `resolve_mtype*`

Only `modelize_mclass` require support for partial context. Furthermore, in
a future PR, it may need to resolve types just before modeling the class
definition (in a place where the `MClass` is available and must be used).

Also include various related cleanups.

Signed-off-by: Jean-Christophe Beaupré <jcbrinfo@users.noreply.github.com>

Pull-Request: #2472

diff --cc src/modelize/modelize_class.nit
Simple merge