Use GraphQL.Client for Scaffolding

[JuanuMusic]

Using GraphQL improves performance and interaction with GraphQL client. Specifically, this was tested using the SpaceX sample but did't work with the Lens API GraphQL. Using GraphQL.Client got rid of the issue and works on both.

[JuanuMusic]

Hey @Giorgi hope you find this improvement helpful.
I thought of using an already existing GraphQL Client instead of having to rely on a custom built.
Maybe this could be implemented on the entire GraphQLinq library.

[JuanuMusic]

@Giorgi I have switched the Serializer to use System.Text instead of Newtonsoft.
In the future it would be ideal to open that as part of the api to let anyone choose, but it would require many considerations on the Scaffolding. (If you are interested I can create that as an issue)

I have also updated the Scaffolding project to .net 7.0 since EnumMemberAttribute doew not work out of the box. (See description on this commit )