PHP 7.0 compatibility

[gongled]

• [x] Build production-ready PHP 7.0.x package for RHEL-based distros
• [x] Implement ability to choose PHP version in PHP role
• [x] Implement ability to setup PHP version on installation stage.

We need to prepare role for compatibility with PHP 7.0 and need to provide the simple way to choose what version do user want to install.