Why:

 * I receive a lot of packages from many different shipping companies.
 * I would like to see in haas how many packages are being delivered.

This change addreses the need by:

 * Adding a sensor for AfterShip (aftership.com)
 * AfterShip supports ~490 couriers world wide thus should cover
   almost any sensible tracking.

Notes:
  - For now this sensor assumes you somehow have added trackings to
    aftership manually.
  - Future idea is to expose service that allows adding a tracking
    based on incoming mails.
  - Other improvments would be to add map markers for package locations.

Related:
- https://community.home-assistant.io/t/package-tracking/858
- https://community.home-assistant.io/t/aftership-package-tracking/24068
- https://community.home-assistant.io/t/aftership-shipment-tracking-platform/14074
- https://community.home-assistant.io/t/aftership-state-card/57912