Adding minimal meta file for Ansible Galaxy.

Should you choose to submit this role to [Ansible Galaxy](https://galaxy.ansible.com/), you will need a `meta/main.yml` file that describes this role. This PR introduces a minimal `meta/main.yml` file so that this role may be used as an Ansible Galaxy role.

The information in this minimal `meta/main.yml` file is based on the README as well as empirical evidence. Feel free to update it as you see fit.

Also included in this PR is a `meta/main.yml.sample` file that was generated by running `ansible-galaxy init`. It lists all possible values for various parts of the `meta/main.yml` file such as `platforms`, `categories`, etc. Please use the values in this file to populate the `meta/main.yml` file.