add conjured items management and refactoring

php/src/Enum/Name.php

@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace GildedRose\Enum;
+
+enum Name: string
+{
+    case AGED_BRIE = 'Aged Brie';
+    case BACKSTAGE_PASSES = 'Backstage passes to a TAFKAL80ETC concert';
+    case SULFURAS = 'Sulfuras, Hand of Ragnaros';
+    case CONJURED = 'Conjured Mana Cake';
+}

php/src/Enum/Operation.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace GildedRose\Enum;
+
+enum Operation: string
+{
+    case INCREASE = 'increase';
+    case DECREASE = 'decrease';
+    case RESET = 'reset';
+}