Add egui as a UI system

src/components.rs

@@ -12,6 +12,11 @@ pub struct Armor {
     pub ac: u32,
 }
 
+#[derive(Component)]
+pub struct Named {
+    pub name: String,
+}
+
 #[derive(Bundle)]
 pub struct Creature {
     pub health: Health,
@@ -20,7 +25,9 @@ pub struct Creature {
 }
 
 #[derive(Component)]
-pub struct PlayerCharacter;
+pub struct PlayerCharacter {
+    pub name: String,
+}
 
 #[derive(Component)]
 pub struct Battle(pub HashMap<u32, Entity>);