render: effectively rename Display to Output, push remaining common code into Renderer task

src/platform/mod.rs

@@ -4,8 +4,9 @@ pub mod embedded_graphics_lib;
 #[cfg(feature="smart-leds")]
 pub mod smart_leds_lib;
 
-use crate::render::{Surface, Display};
+use crate::render::{Surface, Output};
 
 pub trait DisplayInit {
-    fn new_display<S: Surface>() -> impl Display<S>;
+    type Output: Output;
+    fn new_display<S: Surface>() -> Self::Output;
 }