feat: Implemented Inventory.find_free_space

- Added tests for find_free_space

src/inventory/item.rs

@@ -1,3 +1,5 @@
+use std::mem::swap;
+
 use bevy::prelude::*;
 
 #[derive(Component, Clone)]
@@ -32,4 +34,16 @@ impl Item {
         
         !rect.intersect(other_rect).is_empty()
     }
+
+    /// Swap size.x with size.y
+    pub fn swap_size(&mut self) {
+        swap(&mut self.size.x, &mut self.size.y);
+    }
+
+    /// Get clone of item with swapped size
+    pub fn clone_swapped(&self) -> Self {
+        let mut new = self.clone();
+        new.swap_size();
+        new
+    }
 }