introduce a very simple Nextcloud API

Pilz.Networking.CloudProviders.Nextcloud/OCS/APIs/OcsApiLoginFlowV2.cs

@@ -0,0 +1,35 @@
+using Pilz.Networking.CloudProviders.Nextcloud.OCS.Responses.LoginFlowV2;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Pilz.Networking.CloudProviders.Nextcloud.OCS.APIs
+{
+    public class OcsApiLoginFlowV2 : OcsApiBase
+    {
+        private const string OCS_LOGIN_INIT = "/index.php/login/v2";
+
+        public OcsApiLoginFlowV2(OcsApi manager) : base(manager)
+        {
+        }
+
+        public Task<OcsResponseLoginFlowV2?> Init(string url)
+        {
+            return Manager.MakeRequestJson<OcsResponseLoginFlowV2>(HttpMethod.Get, url + OCS_LOGIN_INIT);
+        }
+
+        public Task<OcsResponseLoginFlowV2Credentials?> Poll(OcsResponseLoginFlowV2.PollData poll)
+        {
+            ArgumentNullException.ThrowIfNull(poll?.Endpoint);
+            ArgumentNullException.ThrowIfNull(poll?.Token);
+
+            return Manager.MakeRequestJson<OcsResponseLoginFlowV2Credentials?>(HttpMethod.Get, poll.Endpoint,
+                parameters: new Dictionary<string, string>
+                {
+                    { "token", poll.Token }
+                });
+        }
+    }
+}