Adds grappling gun (#16662)

Content.Shared/Projectiles/ProjectileEmbedEvent.cs

@@ -0,0 +1,7 @@
+namespace Content.Shared.Projectiles;
+
+/// <summary>
+/// Raised directed on an entity when it embeds into something.
+/// </summary>
+[ByRefEvent]
+public readonly record struct ProjectileEmbedEvent(EntityUid Shooter, EntityUid Weapon, EntityUid Embedded);