(#9546) Removing PATH_SEPERATOR from pluginfactdest

This is not needed since only one direcrtory will be used for storing
and retrieving pluginsyncd external facts
(#9546) Retrieve module external fact dir from Puppet::Module

Instead of hard coding the external fact directory for modules and
globbing the directories, it would be accurate to have the
Puppet::Module type perform the lookup logic for external fact
directories.   The facts indirector just needs to make sure those
directories get added to the external fact lookup.