Projectile spells + fireball spell (#9058)

* Projectile spells + fireball spell

* say it with some gumption

Content.Server/Magic/Events/ProjectileSpellEvent.cs

@@ -0,0 +1,20 @@
+using Content.Shared.Actions;
+using Content.Shared.Sound;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom.Prototype;
+
+namespace Content.Server.Magic.Events;
+
+public sealed class ProjectileSpellEvent : WorldTargetActionEvent
+{
+    /// <summary>
+    /// What entity should be spawned.
+    /// </summary>
+    [DataField("prototype", required: true, customTypeSerializer: typeof(PrototypeIdSerializer<EntityPrototype>))]
+    public string Prototype = default!;
+
+    /// <summary>
+    /// Gets the targeted spawn positions; may lead to multiple entities being spawned.
+    /// </summary>
+    [DataField("posData")] public MagicSpawnData Pos = new TargetCasterPos();
+}