Added dirty behavior

Removed restore action (-> Move action wip)
Added additional check on DB size before auto saving
Code cleanup

ModernKeePass/Common/Constants.cs

@@ -0,0 +1,15 @@
+namespace ModernKeePass.Common
+{
+    public class Constants
+    {
+        public class File
+        {
+            public static int OneMegaByte => 1048576;
+        }
+
+        public class Settings
+        {
+            public static string SaveSuspend => nameof(SaveSuspend);
+        }
+    }
+}