Open file from Explorer with association works

Major code refactor in Open, Save and Recent pages and VM
Main page automatically opens a sub page depending on context

ModernKeePass/Events/PasswordEventArgs.cs

@@ -0,0 +1,15 @@
+using System;
+using ModernKeePass.ViewModels;
+
+namespace ModernKeePass.Events
+{
+    public class PasswordEventArgs: EventArgs
+    {
+        public GroupVm RootGroup { get; set; }
+
+        public PasswordEventArgs(GroupVm groupVm)
+        {
+            RootGroup = groupVm;
+        }
+    }
+}