improves hitscan weapons (#248)

- fixes inhand sprite visibility
- adds visible charge level
- refactor sound recourse load, now you can specify fire sound from YAML
- adds laser cannon - more powerful laser
- adds new assets for cannon

Content.Client/GameObjects/Components/Weapons/Ranged/HitscanWeaponVisualizer2D.cs

@@ -0,0 +1,33 @@
+using Content.Shared.GameObjects.Components.Power;
+using Content.Shared.Utility;
+using Robust.Client.GameObjects;
+using Robust.Client.Interfaces.GameObjects.Components;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Utility;
+using YamlDotNet.RepresentationModel;
+
+namespace Content.Client.GameObjects.Components.Power
+{
+    public class HitscanWeaponVisualizer2D : AppearanceVisualizer
+    {
+        private string _prefix;
+
+        public override void LoadData(YamlMappingNode node)
+        {
+            base.LoadData(node);
+
+            _prefix = node.GetNode("prefix").AsString();
+        }
+
+        public override void OnChangeData(AppearanceComponent component)
+        {
+            base.OnChangeData(component);
+
+            var sprite = component.Owner.GetComponent<ISpriteComponent>();
+            if (component.TryGetData(PowerCellVisuals.ChargeLevel, out float fraction))
+            {
+                sprite.LayerSetState(0, $"{_prefix}_{ContentHelpers.RoundToLevels(fraction, 1, 5) * 25}");
+            }
+        }
+    }
+}