Add `lazy_resolvers` to TFL.Package_Namespace
Use MOM.Derived_PNS, not MOM.derive_pns_bases

* And add `MOM.Underived_PNS` for package namespaces based on, but not
  derived from the package namespace `MOM`.

* `Derived_PNS` and `Underived_PNS` lazily resolve names like
  `PAP.Entity` or `Auth.Link1`. They automatically derive package
  specific base classes like `derive_pns_bases` used to do, but only do
  that when such a class is actually used.