Revert "Remove all EF migrations"

This reverts commit bb5b9458e8.

osu.Game/Migrations/20200302094919_RefreshVolumeBindings.cs

@@ -0,0 +1,16 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+namespace osu.Game.Migrations
+{
+    public partial class RefreshVolumeBindings : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.Sql("DELETE FROM KeyBinding WHERE action in (6,7)");
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+        }
+    }
+}