feat(plugins): add web-server plugin (#2726)

* feat(plugins): add web-server plugin

Add support of the cordova-plugin-webserver plugin, to start a
a dynamic content web server on iOS and android devices.

* Update index.ts

src/@ionic-native/plugins/web-server/index.ts

@@ -0,0 +1,110 @@
+import { Injectable } from '@angular/core';
+import { Cordova, IonicNativePlugin, Plugin } from '@ionic-native/core';
+import { Observable } from 'rxjs/Observable';
+
+export interface Response {
+  status: number;
+  body: string;
+  headers: { [key: string]: string};
+}
+
+export interface Request {
+  requestId: string;
+  body: string;
+  headers: string;
+  method: 'POST' | 'GET' | 'PUT' | 'PATCH' | 'DELETE';
+  path: string;
+  query: string;
+}
+
+/**
+ * @name Web Server
+ * @description
+ * This plugin allows you to start a local dynamic content web server for android and iOS devices.
+ *
+ * @usage
+ * ```typescript
+ * import { WebServer } from '@ionic-native/web-server';
+ *
+ *
+ * constructor(private webServer: WebServer) { }
+ *
+ * ...
+ *
+ * this.webServer.onRequest().subscribe(data => {
+ *   console.log(data);
+ *   const res: Response = {
+ *     status: 200,
+ *     body: '',
+ *     headers: {
+ *       'Content-Type': 'text/html'
+ *     }
+ *   };
+ *
+ *   this.webServer.sendResponse(data.requestId, res)
+ *     .catch((error: any) => console.error(error));
+ * });
+ *
+ * this.webServer.start(80)
+ *   .catch((error: any) => console.error(error));
+ *
+ * ```
+ *
+ * @interfaces
+ * Response
+ * Request
+ */
+@Plugin({
+  pluginName: 'WebServer',
+  plugin: 'cordova-plugin-webserver',
+  pluginRef: 'window.webserver',
+  repo: 'https://github.com/bykof/cordova-plugin-webserver.git',
+  platforms: ['Android', 'iOS']
+})
+@Injectable()
+export class WebServer extends IonicNativePlugin {
+
+  /**
+   * This method will start your webserver.
+   * @param port {number} Port number (default to 8080)
+   */
+  @Cordova({
+    callbackOrder: 'reverse',
+  })
+  start(port?: number): Promise<any> {
+    return;
+  }
+
+  /**
+   * This method will stop your webserver.
+   */
+  @Cordova()
+  stop(): Promise<any> {
+    return;
+  }
+
+  /**
+   * This method returns an observable that streams HTTP requests to an observer.
+   * @return {Observable<Request>} Returns an observable to resolve as a Request object
+   */
+  @Cordova({
+    callbackOrder: 'reverse',
+    observable: true,
+    clearFunction: 'stop'
+  })
+  onRequest(): Observable<Request> {
+    return;
+  }
+
+  /**
+   * This method sends a response to a request.
+   * @param requestId {string} Request ID to respond to
+   * @param responseObject {Response} Response object
+   * @return {Promise<any>} Returns a promise that resolves when something happens
+   */
+  @Cordova()
+  sendResponse(requestId: string, responseObject: Response): Promise<any> {
+    return;
+  }
+
+}