changed SAMSHub.addApp to add appDict to _appList and _apps

The new dictionary consists of the two keys app and urlPrefix.
Value for app is the SAMSApp Object value for urlPrefix is the Alias or
the app.name

sams_classes/sams_hub.py

@@ -33,12 +33,13 @@ class SAMSHub:
   def addApp(self, app: SAMSApp = None, alias = None):
     if not isinstance(app, SAMSApp):
       raise TypeError('Argument app has to be a SAMSApp.')
-    self._apps[app.name] = app
-    self._appList.append(app)
+    appDict = {'app': app, 'urlPrefix': (alias or app.name)}
+    self._apps[app.name] = appDict
+    self._appList.append(appDict)
     if app.name == self._config.get('main_app'):
       self._flaskApp.register_blueprint(app.blueprint)
     self._flaskApp.register_blueprint(
-      app.blueprint, url_prefix = '/' + (alias or app.name))
+      app.blueprint, url_prefix = '/' + appDict['urlPrefix'])
   
   @property
   def appKeys(self):