vary wmerrors.ini 'fatal_log_file' per realm

Beta needs the PHP fatal errors to be send to a different UDP receiver
than the one used in production.  This creates a configuration role
class for application servers that let us vary the fatal_log_file.

Hence, instead of calling the configuration class from the module:
applicationserver::config::php, one should include that new role
role::applicationserver::configuration::php.

Change-Id: I212e353b79564e2f909770b0e659414c3988aedd