Implemented support for native module std::weak_ptr

[vmoroz]

This change is to address a customer need to be able to get a std::weak_ptr to a native module in case if the module must subscribe to some events. Since, a native module lifetime is bound to the React instance lifetime, we cannot use this pointer and we better use the std::weak_ptr<T>.
In this PR we enable the native modules to be inherited from the std::enable_shared_from_this<T> that allows use of the weak_from_this() function to get std::weak_ptr<T> to the module.

To support the new functionality we are doing the following changes:

• Introduce a mechanism for a module to associate a custom factory function with a module type.
• In case if custom factory is not provided then we offer two default native module factories:
  • MakeDefaultReactModuleWrapper - the default factory that wraps up native module into ReactNonAbiValue<TModule> to pass the module across the ABI boundary.
  • MakeDefaultSharedPtrReactModuleWrapper - the default factory that wraps up native module into ReactNonAbiValue<shared_ptr<TModule>> in case if module is inherited from std::enable_shared_from_this<T>.

The custom factory can be associated with a module type by providing GetReactModuleFactory function overload that has two arguments Module * pointer type and int. The int parameter is used to give the overload higher priority than the default GetReactModuleFactory function where we use int * when we pass 0 as a second argument.

To show the use of the std::weak_ptr we have added a new SampleSharedCppModule module to the sample project. It shows how the std::weak_ptr can be used with help of the std::enable_shared_from_this base and weak_from_this() method call.

Microsoft Reviewers: Open in CodeFlow

[NikoAri]

[ghost]

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[NickGerleman]

Removing "Backport to 0.62" since we're about to rename it to "Backported to 0.62" as part of backporting label migration. This has been approved to go into 0.62 though, and such has the "Backport approved" label.