Make gcore a std library and remove std, alloc, and more unused features (#2724)

* gcore: remove features `std`, `alloc`, `gpu` and `reflections`, now always available

* gcore: remove non-working features `kurbo` and `log`

node-graph/gcore/src/instances.rs

@@ -142,7 +142,6 @@ impl<T: PartialEq> PartialEq for Instances<T> {
 	}
 }
 
-#[cfg(feature = "dyn-any")]
 unsafe impl<T: StaticType + 'static> StaticType for Instances<T> {
 	type Static = Instances<T>;
 }