Restructure GPU execution to model GPU pipelines in the node graph (#1088)

* Start implementing GpuExecutor for wgpu

* Implement read_output_buffer function

* Implement extraction node in the compiler

* Generate type annotations during shader compilation

* Start adding node wrapprs for graph execution api

* Wrap more of the api in nodes

* Restructure Pipeline to accept arbitrary shader inputs

* Adapt nodes to new trait definitions

* Start implementing gpu-compiler trait

* Adapt shader generation

* Hardstuck on pointer casts

* Pass nodes as references in gpu code to avoid zsts

* Update gcore to compile on the gpu

* Fix color doc tests

* Impl Node for node refs

node-graph/wgpu-executor/src/context.rs

@@ -1,7 +1,7 @@
 use std::sync::Arc;
 use wgpu::{Device, Instance, Queue};
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct Context {
 	pub device: Arc<Device>,
 	pub queue: Arc<Queue>,