LOG-1502: Feature Request: Add UDP toggle flag

[bobziuchkovski]

We use the configure-syslog.py script in conjunction with AWS VPC NAT instances. The NAT instances use CloudFormation init support to retrieve and execute the configure-syslog.py script.

We view the logs for the NAT instances as essentially "best effort" and don't want syslog to hang on the instances in the event our connection to Loggly fails. It would be wonderful if there was a CLI toggle flag to select UDP connections instead of TCP for the generated syslog config template.