Enable Softwarecollections on RHEL and CentOS

As RHEL and CentOS are both longer-lived enterprise-class operating
systems the software versions are usually lagging a bit behind.

In case one wants the longevity of an Enterprise Linux together with
more modern software the Softwarecollections project exists which
offers amongst others more modern PHP releases.

This commit adds a pillar toggle to use the SCL repo and the ability
to select which php version to install.

Added support for Debian 9

Gentoo compat

This will make state names play nicely with gentoo.

add support for 18.04

don't include `include` if it isn't going to include anything else

Mail related PHP Pear system packages

FreeBSD support: ctype & session

php.ng.apache2 & php.ng.composer: FreeBSD support

(Command was not working on Ubuntu 16.04.)
Both Ubuntu's and RedHat's man pages of test list -gt, but not >
as their 'greater than' operator.

added

  - php.ng.filter
  - php.ng.hash
  - php.ng.openssl
  - php.ng.phar

(Command was not working on Ubuntu 16.04.)
Both Ubuntu's and RedHat's man pages of test list -gt, but not >
as their 'greater than' operator.

added

  - php.ng.filter
  - php.ng.hash
  - php.ng.openssl
  - php.ng.phar

This reverts commit d2786dcef6.

fix iteritems for python3