Added FieldDef<'Val, 'Res> to support resolver changing middlewares

[xperiandri]

In order to call Define.Field<'Val>(....).WithAuthorizationPolicy("policy") I need to know not only 'Res which is an object on which FieldDef<'Res> is defined but also a 'Val which is a field type.
However when I introduced FieldDef<'Val, 'Res> F# cannot determine the override between Define.Object that gets a list of field and a labmda that return a list of fields. So I had to rename Define.Object overrie to Define.ObjectRec and Define.Interface override to Define.ObjectRec.
I have not renamed Define.InputObject as it accepts a parameter of list of another interface

[GBirkel]

I'm afraid this one may be beyond my skill to review. I'm not sure what the long-term consequences of changing Object to ObjectRec would be.

[xperiandri]

Anyway we do breaking changes in v2.0
So the main difference is that you need to call Define.ObjectRec to define recursive GraphQL type definitions.
Also there is a question if need to rename Define.InputObject override to Define.InputObjectRec to be consistent or leave it as is to be simple?

[valbers]

I get it.
In any case, I find it a good idea to generally avoid method overloads as F# doesn't support function overloads (although class members may have overloads, just like in our current situation -- which is causing the problem that you're trying to fix), and therefore not having overloads feels more like "the F# way", so I welcome this change already on this level, even if the offending overload were not causing any problems yet.

However, I'm not sure if I agree with the new name. ObjectRec is effectively not by definition recursive, but it can be used for a recursive definition.
That, which ObjectRec actually is, is an Object which takes a function for defining the fields instead of a concrete list of fields.

So, following the nomenclature of the F# core lib, I'd prefer for it to be named something like the defaultWith function of the Option module.

In that case, that could be ObjectHavingFieldsWith (instead of ObjectRec).
What do you think?

[GBirkel]

Have the changes requested by valbers been addressed?

[xperiandri]

@njlr give your opinion, please

[valbers]

@xperiandri could you please do less force-pushes with commit amendments? It makes it hard to follow what you actually changed with each commit amendment. I mean: once in a while it's ok, but I see this now very often.

[Thorium]

Was the # removed on purpose?

[xperiandri]

I either got a warning or error because of this

[valbers]

I gave you my two cents with regard to the naming of ObjectRec, but it seems like you don't agree with it. I don't want to die on that hill, so I'm approving this PR.

[xperiandri]

I just want to check again if it still the issue.
And I cannot decide on naming 🙂

[xperiandri]

@valbers I implemented an alternative solution #492