added Photon Service & interface

src/app/photon.service.ts

@@ -0,0 +1,18 @@
+import { Injectable } from '@angular/core';
+import { HttpClient } from '@angular/common/http';
+import { Photon } from './interfaces/photon';
+import { Observable } from 'rxjs';
+
+@Injectable({
+  providedIn: 'root'
+})
+
+// communicates with Photon (https://photon.komoot.io/)
+export class PhotonService{
+  constructor(private http: HttpClient) { }
+
+  // sends a query request to Photon and gets response (https://photon.komoot.io/)
+  sendQueryRequest(q: string): Observable<Photon[]> { 
+    return this.http.get<Photon[]>("https://photon.komoot.io/api/?q=" + q);
+  }
+}