Add CLI option for APIGW access token

[pritidesai]

wskdeploy supports auth, host, api on CLI:

Flags:
      --apihost HOST         whisk API HOST
      --apiversion VERSION   whisk API VERSION
  -u, --auth KEY             authorization KEY
  -c, --cert string          path of the .cert file
...

Add APIGW Access Token as well on CLI.