Add Molecule Tests

[rcuza]

This change adds molecule tests and removed the Vagrant based tests. It also updates .travis.ym to run the new tests.

To run the tests, install molecule (in a virtualenv works fine with python 2.7) and then run molecule test from the root of the repo.

The tests were written with the Docker driver to improve compatibility with CI.

To see the results of the tests, you can go to https://travis-ci.org/rcuza/ansible-logrotate. Test number 6 was an intentional failed build so you can see how it catches errors.

Thank you for making your original code available.

[rcuza]

@nickhammond,

After taking a look @geerlingguy ansible-role-ansible I realized my original test was testing running the same docker image on different operating systems. What I wanted to test is the role on docker containers running different operating systems (duh). This PR now does that.

I also realize my learning curve with TravisCI is showing in the number of commits in this PR. If you are need me to squash them please let me know.