ipaplatform: Let fedora path module use PathNamespace class

https://fedorahosted.org/freeipa/ticket/4052
ipaplatform: Link to platform module during build time

https://fedorahosted.org/freeipa/ticket/4052
ipaplatform: Pylint fixes

https://fedorahosted.org/freeipa/ticket/4052
ipaplatform: Contain all the tasks in the TaskNamespace

https://fedorahosted.org/freeipa/ticket/4052
ipaplatform: Move hardcoded paths from Fedora platform files to path namespace

Part of: https://fedorahosted.org/freeipa/ticket/4052