introduce a very simple Nextcloud API

Pilz.Networking.CloudProviders.Nextcloud/Model/UserBackendCapabilities.cs

@@ -0,0 +1,22 @@
+using Newtonsoft.Json;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Pilz.Networking.CloudProviders.Nextcloud.Model
+{
+    public class UserBackendCapabilities
+    {
+        /// <summary>
+        /// Defines if the display name can be changed.
+        /// </summary>
+        public bool SetDisplayName { get; set; }
+
+        /// <summary>
+        /// Defines if the password can be changed.
+        /// </summary>
+        public bool SetPassword { get; set; }
+    }
+}