Add attribute system with core stats and gameplay components

GameCore/Attributes/Attribute.cs

@@ -0,0 +1,31 @@
+namespace GameCore.Attributes;
+
+/// <summary>
+///     Defines all possible stats an entity can have.
+/// </summary>
+public enum Attribute
+{
+    // Core Stats
+    Health,
+    MaxHealth,
+    Armor,
+    MoveSpeed,
+    Acceleration,
+    Friction,
+    JumpHeight,
+
+    // Combat Stats
+    Damage,
+    AttackSpeed,
+    AttackRange,
+    MeleeDamage, // Multiplier
+    RangedDamage, // Multiplier
+
+    // Progression
+    Level,
+    Experience,
+    ExperienceToNextLevel,
+
+    // Misc
+    Luck
+}