Ansible documentation

[ogenstad]

All of the modules in https://github.com/napalm-automation/napalm-ansible have documentation in the same way that the modules within Ansible does.

However unlike Ansible the documentation isn't available online outside of the source code. For the hackathon we could use this information to publish the documentation on https://napalm.readthedocs.io/en/latest/.

For this to happen we need to create tests to validate format of the current documentation and create a hook in Travis so that a new release of the Ansible modules would trigger a new build of the documentation for the https://github.com/napalm-automation/napalm repo.