update the voucher

[JasonBourne1998]

Fix the 404 error (issue #271 ) on the voucher service by adding the cross-site function in the script. However, this is still something to do to get a 200 code:

1. After deploying the voucher service, use the command "kubectl port-forward --address 0.0.0.0 service/ts-voucher-service 16101:16101" to forward the voucher port.
2. Edit the corresponding ajax query URL in the ts-ui-dashboard ( url: "/getVoucher",) with the server's IP+16101/getVoucher. i.e: (http://server IP:16101/getVoucher)
3. After deploying the UI service, use the command "kubectl port-forward --address 0.0.0.0 service/ts-ui-dashboard 31303:8080" to forward the UI port. (I use this to access "train-ticket" from an external server using the IP address. see issue How to access the ui on the externel ip? #265 )
4. Then you can get a 200 status code when browsing the voucher.