Re-organize all projects (#4166)

Content.Server/Cooldown/ItemCooldownSystem.cs

@@ -0,0 +1,34 @@
+using System;
+using Content.Shared.Cooldown;
+using Robust.Shared.GameObjects;
+
+namespace Content.Server.Cooldown
+{
+    public class ItemCooldownSystem : EntitySystem
+    {
+        public override void Initialize()
+        {
+            base.Initialize();
+
+            SubscribeLocalEvent<ItemCooldownComponent, RefreshItemCooldownEvent>(OnItemCooldownRefreshed);
+        }
+
+        public void OnItemCooldownRefreshed(EntityUid uid, ItemCooldownComponent comp, RefreshItemCooldownEvent args)
+        {
+            comp.CooldownStart = args.LastAttackTime;
+            comp.CooldownEnd = args.CooldownEnd;
+        }
+    }
+
+    public class RefreshItemCooldownEvent : EntityEventArgs
+    {
+        public TimeSpan LastAttackTime { get; }
+        public TimeSpan CooldownEnd { get;  }
+
+        public RefreshItemCooldownEvent(TimeSpan lastAttackTime, TimeSpan cooldownEnd)
+        {
+            LastAttackTime = lastAttackTime;
+            CooldownEnd = cooldownEnd;
+        }
+    }
+}