feat: modify Connection to allow optionally disable nodes field in gql output. Keep nodes field enabled by default.

[xoac]

This is different approach of #1215

In case of next major release would be good to consider returning edges field through additional_fields (If this will be possible because of reference to edges). This would simplify Connection structure

[sunli829]

I merged #1215 because it seemed simpler, what do you think? 🙂

[xoac]

Diff between #1218 and #1215:

• 1218 is not breaking change (according to cargo feature documentation and sem-ver)
• Connection with and without nodes can be used in the same code
• if our crate will depends on async-graphql indirectly we can lose control over enabling/disabling nodes

• 1218 complicates already complicated Connection strucutre

I don't have strong opinion what is better. In my case both solution will works.

[sunli829]

Connection with and without nodes can be used in the same code

You're right, I didn't think about that. 🙂