add type to modules created by LoadHookContext

Modules created by a LoadHookContext do not currently set a module type
when creating new modules, but it would make analysis of the
module-graph.json much easier if this module type information was available.

Bug: 174879786
Test: m json-module-graph && check that module which previously had a
    blank module type now have the field populated
Change-Id: I3be5d259694a1540d21deb8a665ec7bea3464054