Add frontend speed test application and server setup

* Introduced a new HTML frontend for network speed testing with a responsive UI
* Implemented backend server functionality to serve the frontend and handle speed test APIs
* Added speed test logic for downloading and uploading data, including progress tracking and result validation
* Created README-SPEEDTEST.md for documentation on application architecture, setup, and usage.
* Updated package.json to include necessary scripts and dependencies for development and testing

src/net/http/HttpMethod.ts

@@ -0,0 +1,52 @@
+import {assertUnreachable} from '@techniker-me/tools';
+
+export enum HttpMethod {
+  GET = 0,
+  POST = 1,
+  PUT = 2,
+  DELETE = 3,
+  PATCH = 4,
+  OPTIONS = 5
+}
+
+export type HttpMethodType = keyof typeof HttpMethod;
+
+export class HttpMethodMapping {
+  public static convertHttpMethodTypeToHttpMethod(method: HttpMethodType): HttpMethod {
+    switch (method) {
+      case 'GET':
+        return HttpMethod.GET;
+      case 'POST':
+        return HttpMethod.POST;
+      case 'PUT':
+        return HttpMethod.PUT;
+      case 'DELETE':
+        return HttpMethod.DELETE;
+      case 'PATCH':
+        return HttpMethod.PATCH;
+      case 'OPTIONS':
+        return HttpMethod.OPTIONS;
+      default:
+        assertUnreachable(method);
+    }
+  }
+
+  public static convertHttpMethodToHttpMethodType(method: HttpMethod): HttpMethodType {
+    switch (method) {
+      case HttpMethod.GET:
+        return 'GET';
+      case HttpMethod.POST:
+        return 'POST';
+      case HttpMethod.PUT:
+        return 'PUT';
+      case HttpMethod.DELETE:
+        return 'DELETE';
+      case HttpMethod.PATCH:
+        return 'PATCH';
+      case HttpMethod.OPTIONS:
+        return 'OPTIONS';
+      default:
+        assertUnreachable(method);
+    }
+  }
+}