Move network import type from NodeInput::Network to NodeNetwork in order to enable automatic Into node insertion

[adamgerhant]

Instead of annotating type for each NodeInput::network usage, the types should be annotated in a single vec for every import. For example we do something like

pub fn node(input1){
  subnode(input1: String)
  subnode(input1: String)
  etc
}

rather than

pub fn node(input1: String){
  subnode(input1)
  subnode(input1)
  etc
}

Technically I dont think we even need to annotate the parameters, since their types can be resolved at compile time. However, this system would be useful/necessary for automatic into node insertion (#1890, which can also be used to solve #1919), as well as displaying what types can be connected to a node when hovering over the input.

Discussions here: https://discord.com/channels/731730685944922173/731738914812854303/1253116397370998794 https://discord.com/channels/731730685944922173/860830913390575646/1271586374314885201 https://discord.com/channels/731730685944922173/860830913390575646/1271605307771981987

And a more recent recap asking for a reminder about what this is and its status: https://discord.com/channels/731730685944922173/1059075292414619689/1387941282701119550