Restcall Widget specs
RestCall widget is now loadable with an id or request model
- the view of this widget is not yet implemented
added  test case to restCallWidgetSpecs.js
Created rest-call widget view
- updated angular material
navigation added
- when client is phone, navigation is available via swipe or clicking on the menu
- when client is tablet or a bigger device, navigation will be shown directly
Switch to light-green theme from angular material
added saving of execution
    * execution through workflow completed
    * additional saving of headers, data, request method
    * removed GET /workflow/xxx/execute, created POST /workflow/xxx/executions -> more REST like
added possibility to execute single apicalls
    * execution of single api calls
    * list all executions of an apicall
added executedAt to single api call executions