Change IUserContext

[Shane32]

This PR changes IUserContext to inherit from IDictionary<string, object> so that it can be stored directly within IResolveFieldContext.UserContext.

Advantages:

• no wrapping/unwrapping of the user context
• more 'native' with other builder methods provided by GraphQL.NET and the server project

See:

• https://github.com/graphql-dotnet/server/blob/master/src/Transports.AspNetCore/Extensions/GraphQLBuilderExtensions.cs#L24..L71

However:

• It may not be obvious that in order for the conventions project to utilize a user context, it must implement IUserContext in addition to IDictionary<string, object>, the only requirement for the AddUserContextBuilder<TUserContext> method within the server project.
• User code now needs to change their IUserContext implementation to inherit from Dictionary<string, object>
• The user context implementation now has many default methods and properties besides the ones defined by the user.

Possible helper "solution" we could provide: provide a UserContext base class which exposes no members except through the implemented IDictionary<string, object> interface. Users can inherit from this class, and their strongly-typed class will not show any dictionary members on it.

[tlil]

Possible helper "solution" we could provide: provide a UserContext base class which exposes no members except through the implemented IDictionary<string, object> interface. Users can inherit from this class, and their strongly-typed class will not show any dictionary members on it.

Yes, we can have a UserContextBase class like you suggest, implementing IDictionary<string, object> as a helper class

[Shane32]

Yes, we can have a UserContextBase class like you suggest, implementing IDictionary<string, object> as a helper class

See attached. Folder / namespace?

[tlil]

See attached. Folder / namespace?

As-is works for me. Thanks