Replace tracing with log (#2928)

* Replace tracing crate with log

It's just so much simpler to use

* Add `bacon wasm` job

* eframe: add a WebLogger for piping log events to the web console

crates/egui_demo_app/src/apps/custom3d_glow.rs

@@ -89,7 +89,7 @@ impl RotatingTriangle {
             let program = gl.create_program().expect("Cannot create program");
 
             if !shader_version.is_new_shader_interface() {
-                tracing::warn!(
+                log::warn!(
                     "Custom 3D painting hasn't been ported to {:?}",
                     shader_version
                 );