Implement node graph gpu execution via vulkano and rust gpu (#870)

* Add Executor abstraction

* Resolve inputs for proto nodes by adding compose nodes

* Add infrastructure for compiling gpu code

* Integrate nodegraph gpu execution into graph-crafter

* Extract graphene core path from env vars

* Make Color struct usable for gpu code

node-graph/gcore/src/gpu.rs

@@ -0,0 +1,8 @@
+use bytemuck::{Pod, Zeroable};
+
+#[repr(C)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Pod, Zeroable)]
+pub struct PushConstants {
+	pub n: u32,
+	pub node: u32,
+}