Now GetCart returns an empty cart for non-existing user
(user that haven't added anything to the cart before)
Added test to cover that
Also enhanced windows script for running cart service locally.
Now we have two options:
- Running the service and redis locally (assuming redis emulator is installed)
This is good for easier local debugging and troubleshooting
docker_setup local
- Running the service and redis in two separate docker containers
This is good for better simulation of what will happen in the cloud
