Add shop supplies and rebalance early economy

items/catalog/cooler_expansion.tres

@@ -0,0 +1,17 @@
+[gd_resource type="Resource" script_class="ItemData" load_steps=3 format=3]
+
+[ext_resource type="Script" path="res://items/item_data.gd" id="1"]
+[ext_resource type="Texture2D" path="res://items/icons/placeholder/cooler_expansion.svg" id="2"]
+
+[resource]
+script = ExtResource("1")
+item_id = &"cooler_expansion"
+display_name = "Cooler Expansion"
+description = "Permanently increases the number of fish the Cooler can hold."
+category = 4
+icon = ExtResource("2")
+stackable = false
+max_stack = 1
+usable = false
+equippable = false
+hotbar_allowed = false