Fix/fpm freebsd

[sticky-note]

Add minimum default to get nginx.ng.fpm state works on FreeBSD

• replaced user and group of pool directory by vars lookup in map.jinja
• default user/group added for all other OS to don't produce breaking changes
• added fpm default conf for Freebsd
• Tested on FreeBSD and Debian with a custom pool placed in pillar

[johnkeates]

Works on my side as well!

[sticky-note]

thanks <3