Centralise and share bar line generation code between rulesets

osu.Game/Rulesets/Objects/BarLine.cs

@@ -0,0 +1,16 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+namespace osu.Game.Rulesets.Objects
+{
+    /// <summary>
+    /// A hit object representing the end of a bar.
+    /// </summary>
+    public class BarLine : HitObject
+    {
+        /// <summary>
+        /// Whether this barline is a prominent beat (based on time signature of beatmap).
+        /// </summary>
+        public bool Major;
+    }
+}