Adds missing providedIn declaration for services

src/app/shared/error-handler.ts

 import { isPlatformBrowser, LocationStrategy, PathLocationStrategy } from '@angular/common';
 import { ErrorHandler, Inject, Injectable, Injector, PLATFORM_ID } from '@angular/core';
 
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class GlobalErrorHandler implements ErrorHandler {
   private _errorMap = [];
 

src/app/shared/tracking/ArsnovaClickAngulartics2Piwik.ts

@@ -6,7 +6,7 @@ import { INamedType } from '../../lib/interfaces/interfaces';
 
 declare var _paq: any;
 
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class ArsnovaClickAngulartics2Piwik extends Angulartics2Piwik {
 
   constructor(private _angulartics2: Angulartics2, private route: ActivatedRoute) {