Refactor Api-Client

Add Exceptionhandler, AlertService JSON-Converter
AppSettings via DI

Reformat Code

Jugenddienst Stunden/Infrastructure/AlertService.cs

@@ -0,0 +1,15 @@
+using Jugenddienst_Stunden.Interfaces;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Jugenddienst_Stunden.Infrastructure;
+
+internal sealed class AlertService : IAlertService {
+	public event EventHandler<string>? AlertRaised;
+	public void Raise(string message) {
+		AlertRaised?.Invoke(this, message);
+	}
+}