Gun refactor (#8301)

Co-authored-by: Kara <lunarautomaton6@gmail.com>
Co-authored-by: T-Stalker <le0nel_1van@hotmail.com>
Co-authored-by: T-Stalker <43253663+DogZeroX@users.noreply.github.com>
Co-authored-by: ElectroJr <leonsfriedrich@gmail.com>
Co-authored-by: metalgearsloth <metalgearsloth@gmail.com>

Content.Shared/Weapons/Ranged/Systems/SharedTetherGunSystem.cs

@@ -0,0 +1,34 @@
+using Robust.Shared.Map;
+using Robust.Shared.Serialization;
+
+namespace Content.Shared.Weapons.Ranged.Systems;
+
+public abstract class SharedTetherGunSystem : EntitySystem
+{
+    protected const string CommandName = "tethergun";
+}
+
+[Serializable, NetSerializable]
+public sealed class StartTetherEvent : EntityEventArgs
+{
+    public EntityUid Entity;
+    public MapCoordinates Coordinates;
+}
+
+[Serializable, NetSerializable]
+public sealed class StopTetherEvent : EntityEventArgs {}
+
+[Serializable, NetSerializable]
+public sealed class TetherMoveEvent : EntityEventArgs
+{
+    public MapCoordinates Coordinates;
+}
+
+/// <summary>
+/// Client can't know the tether's <see cref="EntityUid"/> in advance so needs to be told about it for prediction.
+/// </summary>
+[Serializable, NetSerializable]
+public sealed class PredictTetherEvent : EntityEventArgs
+{
+    public EntityUid Entity;
+}