Refactor Api-Client

Add Exceptionhandler, AlertService JSON-Converter
AppSettings via DI

Reformat Code

Jugenddienst Stunden/Infrastructure/Exceptions.cs

@@ -0,0 +1,23 @@
+using System.Net;
+
+namespace Jugenddienst_Stunden.Infrastructure;
+
+internal class ApiException : Exception {
+	public HttpStatusCode StatusCode { get; }
+	public string? ResponseBody { get; }
+
+	public ApiException(string message, HttpStatusCode statusCode = 0, string? responseBody = null,
+		Exception? inner = null)
+		: base(message, inner) {
+		StatusCode = statusCode;
+		ResponseBody = responseBody;
+	}
+
+	public static ApiException From(HttpStatusCode statusCode, string message, string? responseBody = null)
+		=> new ApiException(message, statusCode, responseBody);
+}
+
+internal class ValidationException : Exception {
+	public ValidationException(string message) : base(message) {
+	}
+}