Rewrite debops.debops to support current project

This role will now only manage DebOps scripts, playbooks and roles
system-wide (playbooks and roles are not installed by default). Ansible
will be installed via a Debian package, which can be optionally disabled
using a variable. Dependency on 'debops.ansible' role is dropped.
Merge pull request #1 from drybjed/rewrite-role

Rewrite debops.debops to support current project