* Worker.cs: Randomized wait time in case of retries.
Use request-test of a well known app to decide whether to dequeue an
  app url.

* Consts.cs: Added a new const WELLKNOWN_APP_URL.
Changed the database connection settings.
* Worker.cs: Randomized the waiting time in case of retries.
Test request for a predefined wellknown app prio dequeuing an app.

* Consts.cs: Updated the database connection settings.
Added a new const WELLKNOWN_APP_URL.