Mod naming rule and engine UI in engine mods

Mods are renamed by role (shell2d_base, menu_base, ui_base, live2d_base,
editor_tools, cthangover_story, cthangover_murakami, cthangover_party) and
every reference follows. Engine UI prefabs (dialog, answers, message, game
menu, inventory, map, skills) and their panel entries moved out of the story
mod into the subsystem mods; the card_novel and vn_starter_novel collections
are removed.

scenes/ui/inventory_item.tscn

@@ -0,0 +1,10 @@
+[gd_scene format=3]
+
+[ext_resource type="Script" path="res://mods/items_base/src/ui/InventoryItemBehaviour.cs" id="1"]
+
+[node name="InventoryItem" type="Control"]
+layout_mode = 3
+anchors_preset = 0
+size_flags_horizontal = 3
+size_flags_vertical = 3
+script = ExtResource("1")