build: update Angular to v7.2.15 (#412)

- Update to Angular 7
- Update all dependencies to their latest versions
- Refactor tslint configuration and rules
- Update travis to use Angular 7
- Refactor forkJoin to remove tslint error

Fixes: #407

src/app/system/manage-scheduler-jobs/manage-scheduler-jobs.resolver.ts

@@ -24,10 +24,10 @@ export class ManageSchedulerJobsResolver implements Resolve<Object> {
    * @returns {Observable<any>}
    */
   resolve() {
-    return forkJoin(
+    return forkJoin([
       this.systemService.getJobs(),
       this.systemService.getScheduler()
-    );
+    ]);
   }
 
 }