Add in roles data validation

Add in roles data validation

With the merging of Iad3e9b215c6f21ba761c8360bb7ed531e34520e6 the
roles_data.yaml should be generated with tripleoclient rather than
edited. This change adds in a pep8 task to verify that the appropriate
role files in roles/ have been modified to match how our default
roles_data.yaml is constructed.  Additionally this change adds a new tox
target called 'genrolesdata' that will all you to automatically generate
roles_data.yaml and roles_data_undercloud.yaml

Change-Id: I5eb15443a131a122d1a4abf6fc15a3ac3e15941b
Related-Blueprint: example-custom-role-environments