Allow most libraries to reserve capacity for their database.

src/Library/ItemLibrary.hpp

@@ -11,7 +11,8 @@ namespace CreatureLib::Library {
         std::unordered_map<std::string, const Item*> _items;
 
     public:
-        ItemLibrary() = default;
+        ItemLibrary(size_t initialCapacity = 32)
+            : _items(std::unordered_map<std::string, const Item*>(initialCapacity)){};
         ~ItemLibrary() { _items.clear(); }
 
         [[nodiscard]] const Item* GetItem(const std::string& name) const;