rewrite CosmicEdit to be more bevy-ish

also break all tests and examples whoooops

examples/bevy_api_testing.rs

+use bevy::prelude::*;
+use bevy_cosmic_edit::{
+    ActiveEditor, CosmicEditPlugin, CosmicEditSpriteBundle, CosmicEditUiBundle,
+};
+
+fn setup(mut commands: Commands) {
+    commands.spawn(Camera2dBundle::default());
+
+    // spawn a new CosmicEditBundle
+    commands.spawn(CosmicEditUiBundle {
+        style: Style {
+            // Size and position of text box
+            width: Val::Px(300.),
+            height: Val::Px(50.),
+            left: Val::Px(100.),
+            top: Val::Px(100.),
+            ..default()
+        },
+        ..default()
+    });
+
+    let sprite_editor = commands
+        .spawn(CosmicEditSpriteBundle {
+            sprite: Sprite {
+                // Sets size of text box
+                custom_size: Some(Vec2::new(300., 100.)),
+                ..default()
+            },
+            // Position of text box
+            transform: Transform::from_xyz(100., 200., 0.),
+            ..default()
+        })
+        .id();
+
+    commands.insert_resource(ActiveEditor {
+        entity: Some(sprite_editor),
+    });
+}
+
+fn main() {
+    App::new()
+        .add_plugins(DefaultPlugins)
+        .add_plugins(CosmicEditPlugin::default())
+        .add_systems(Startup, setup)
+        .run();
+}