Improves examine code

Examining now has larger range. Ghosts have no range limit.
Fixed some messy code and some bad netcode.

Content.Shared/GameObjects/EntitySystems/ExamineSystemShared.cs

@@ -0,0 +1,35 @@
+using Content.Shared.GameObjects.Components.Mobs;
+using JetBrains.Annotations;
+using Robust.Shared.GameObjects.Systems;
+using Robust.Shared.Interfaces.GameObjects;
+
+namespace Content.Shared.GameObjects.EntitySystems
+{
+    public abstract class ExamineSystemShared : EntitySystem
+    {
+        public const float ExamineRange = 8f;
+        public const float ExamineRangeSquared = ExamineRange * ExamineRange;
+
+        [Pure]
+        protected static bool CanExamine(IEntity examiner, IEntity examined)
+        {
+            if (!examiner.TryGetComponent(out ExaminerComponent examinerComponent))
+            {
+                return false;
+            }
+
+            if (!examinerComponent.DoRangeCheck)
+            {
+                return true;
+            }
+
+            if (examiner.Transform.MapID != examined.Transform.MapID)
+            {
+                return false;
+            }
+
+            var delta = examined.Transform.WorldPosition - examiner.Transform.WorldPosition;
+            return delta.LengthSquared <= ExamineRangeSquared;
+        }
+    }
+}