Refactor MeleeWeaponComponent and related comps to be ECS (#4133)

* move everything to MeleeWeaponSystem

* refactor MeleeChemicalInjector

* hypospray and flash refactor

* stunbaton refactor

* bugfixes

* flash afterinteract

* resolve issues

* props

* playing the slots

* MeleeInteractEvent + bugfixes

* spear can actually use MeleeChemicalInjector

Content.Server/GameObjects/EntitySystems/HypospraySystem.cs

@@ -0,0 +1,35 @@
+using Content.Server.GameObjects.Components.Chemistry;
+using Content.Shared.Interfaces.GameObjects.Components;
+using Robust.Shared.GameObjects;
+
+namespace Content.Server.GameObjects.EntitySystems
+{
+    public class HypospraySystem : EntitySystem
+    {
+        public override void Initialize()
+        {
+            base.Initialize();
+
+            SubscribeLocalEvent<HyposprayComponent, AfterInteractEvent>(OnAfterInteract);
+            SubscribeLocalEvent<HyposprayComponent, ClickAttackEvent>(OnClickAttack);
+        }
+
+        public void OnAfterInteract(EntityUid uid, HyposprayComponent comp, AfterInteractEvent args)
+        {
+            if (!args.CanReach)
+                return;
+            var target = args.Target;
+            var user = args.User;
+
+            comp.TryDoInject(target, user);
+        }
+
+        public void OnClickAttack(EntityUid uid, HyposprayComponent comp, ClickAttackEvent args)
+        {
+            var target = args.TargetEntity;
+            var user = args.User;
+
+            comp.TryDoInject(target, user);
+        }
+    }
+}