Remove surface and window from ApplicationIo (#3941)

* Remove surface and window from ApplicationIo

* Seperate Wasm and Native ApplicationIo

* Fix warnings

* Fix tests

* Remove redundant PlatformApplicationIo::new_offscreen

* Fixup

* Remove unused From implementaitions for ApplicationIo

node-graph/libraries/canvas-utils/src/lib.rs

@@ -0,0 +1,8 @@
+//! A collection of utilities for working with HTML canvases.
+//! This library is designed to be used in a WebAssembly context.
+//! It doesn't expose any functionality when compiled for non-WebAssembly targets
+
+#[cfg(target_family = "wasm")]
+mod wasm;
+#[cfg(target_family = "wasm")]
+pub use wasm::*;