Improve base Rakefile
Improve base Rakefile

Update the Rakefile to be more inline with what is setup when a new
module is created via puppet module generate.

This Rakefile differs in that it sets default tasks to run wich is all
the basic validation, rspec and linting tests

Signed-off-by: Andrew Grimberg <1f872228929e751eea07667e68fbb1655199bd12@linuxfoundation.org>

tykeal/puppet-nexus,ixxus/puppet-nexus,hubspotdevops/puppet-nexus,tykeal/puppet-nexus,hubspotdevops/puppet-nexus