Moved logrotate to a module

Will eventually move this into upstream ansible.  Wanted to write as a role
module first, since my development env was already setup.

Since roles are evaluated on the server, and jinja2 is not available, opted
to keep deps at a minimum, using the hackish string formatting.
Merge pull request #3 from retr0h/retr0h/logrotate-module

Moved logrotate to a module