Rename vars dir and file

I don't use per hosts vars at present.
Add private vars file

Ignore vars/private.yaml.
Copy vars/private.sample.yaml to private.yaml, and edit it.
MTA is Postfix. Only relay to smtp.gmail.com.
Install Ansibles.logwatch
Install Ansibles.perl
Install Ansibles.cron
logwatch: mail to senosa@gmail.com
postfix: set myhostname and mydomain for vagbox.dev
Install Ansibles.ntp
ntp: ntp.jst.mfeed.ad.jp, ntp.nict.jp

Add `disable monitor` ref (https://www.jpcert.or.jp/at/2014/at140001.html)
Install Ansibles.monit
postfix: use default for mydomain
monit: monitoring sshd, cron, ntp, postfix
Remove monitoring roll written by me
Install Ansibles.fail2ban
fail2ban: monitoring ssh
Install Ansibles.build-essential
build-essential: install
Install Ansibles.git
git: Install git 2.0.0 from source