Validate ruby file layout in module

[sanfrancrisko]

Originally reported in PDK-677 by @DavidS :

ruby files under lib must match specific criteria so that they do not break pluginsync:

the entire pathname has to be shorter than ~200 characters to avoid breaking on windows (need to verify exact number on a windows machine)
files in lib/puppet_x/ must be namespaced to forgename, and modulename

Acceptance Criteria:
pdk validate checks the criteria in the description and provides appropriate error messages if violated