Simplification of Php role setup

It adds a map for role packages, which are required and need to be installed if they are common to two different roles.

Example:

    The role Php defines that the package `php5-mysql` needs to be installed if MySQL(or MariaDB) were selected for installation.

This started as a simplification of the _setup_ method in the Php role, since the Scrutinizer report shows that the complexity [got worst](https://scrutinizer-ci.com/g/Phansible/phansible/inspections/0ede1679-bf54-4018-a143-dbef4ac68656/code-structure/operation/Phansible%5CRoles%5CPhp%3A%3Asetup).

In the future, we can make this automatic for all roles, and include the process of adding packages in the BaseRole.