Refactored Application Auto Scaling code example (#739)

* Refactored Application Auto Scaling code example to move operation out of main and into separate function.

* Updated Application Auto Scaling code example to include unit test and readme

* Updated change log with info about latest changes to Application Auto Scaling code example

* Removed unit test from Application Auto Scaling code example.

* Updated Application Auto Scaling code example--edited readme, reset args to separate function.

* Remove `actix-rt` dependency

* Fix typo