Reduce Triggers Boilerplate. (#41086)

* Push 1

* cleanup + master merge

* launchontrigger

* A crumb of cleanup

---------

Co-authored-by: Princess Cheeseballs <66055347+Pronana@users.noreply.github.com>

Content.Shared/Trigger/SharedTriggerSystems.cs

@@ -0,0 +1,41 @@
+using Content.Shared.Trigger.Components.Effects;
+using Content.Shared.Trigger.Systems;
+
+namespace Content.Shared.Trigger;
+
+/// <summary>
+/// This is a base Trigger system which handles all the boilerplate for triggers automagically!
+/// </summary>
+public abstract class TriggerOnXSystem : EntitySystem
+{
+    [Dependency] protected readonly TriggerSystem Trigger = default!;
+}
+
+/// <summary>
+/// This is a base Trigger system which handles all the boilerplate for triggers automagically!
+/// </summary>
+public abstract class XOnTriggerSystem<T> : EntitySystem where T : BaseXOnTriggerComponent
+{
+    /// <inheritdoc/>
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeLocalEvent<T, TriggerEvent>(OnTrigger);
+    }
+
+    private void OnTrigger(Entity<T> ent, ref TriggerEvent args)
+    {
+        if (args.Key != null && !ent.Comp.KeysIn.Contains(args.Key))
+            return;
+
+        var target = ent.Comp.TargetUser ? args.User : ent.Owner;
+
+        if (target is not { } uid)
+            return;
+
+        OnTrigger(ent, uid, ref args);
+    }
+
+    protected abstract void OnTrigger(Entity<T> ent, EntityUid target, ref TriggerEvent args);
+}