create Device namespace and getStateType function

src/app/services/device.service.ts

@@ -1,9 +1,10 @@
 import { Injectable } from '@angular/core';
+import Device from '../device';
 
 @Injectable({
   providedIn: 'root'
 })
 export class DeviceService {
-
+  private devices: Device[];
   constructor() { }
 }

src/app/services/system-config.service.ts

@@ -5,8 +5,7 @@ import { Observable, Subject } from 'rxjs';
 import { map, retry } from 'rxjs/operators';
 
 import Folder from '../folder';
-import { Device } from '../device';
-import { CookieService } from './cookie.service';
+import Device from '../device';
 import { environment } from '../../environments/environment'
 import { apiURL, apiRetry } from '../api-utils'