Breaking change: All ProvideFactory* functions(and ServiceFatory* structs) now accept 2 type parameters along with factory parameters, the first one must always be explicitly passed. Their combinations may fall into 2 categories

• The first one is an interface and the second is a concrete type:
  pal.ProvideFactory1[Pinger](func(_ context.Context, url string) (*pinger, error) {...}). In this case the returned value(*pinger) must implement the interface(Pinger).
• The first one and the second one are of the same type:
  pal.ProvideFactory1[*pinger](func(_ context.Context, url string) (*pinger, error) {...})

This is validated in runtime during initialization. The factory function must always return a pointer to a concrete type.

This is done to let pal inspect dependencies of services created by factory functions and build the correct dependency tree.

The actual changes to the dependency tree to embrace these changes will come in a follow up pr.