[refactor] templates/debian_ip/debian_eth.jinja
[refactor] templates/debian_ip/debian_eth.jinja

- Turns list of options into loop, from long list of static if's
- Drops the (nearly redundant) separate IPv4/v6 block
- Allows all options to be space-delimited list, line-delimited list, or string
- Removes extraneous newlines in interfaces file

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt