refactor projections into their own module

src/main.rs

@@ -9,6 +9,7 @@ use crate::scene::*;
 use crate::utils::*;
 use crate::viewer::*;
 
+
 use bevy::{prelude::*, window::PresentMode, render::camera::CameraProjectionPlugin};
 use offaxis::{offaxis_camera_setup, OffAxisProjection};
 
@@ -17,6 +18,7 @@ mod scene;
 mod screeninfo;
 mod utils;
 mod viewer;
+mod projection;
 
 fn main() {
     App::new()