pool.pp: add new define ceph::pool

Added new ceph::pool to manage pools. Currently these actions are supported:
- create a new pool
- delete an existing pool from the cluster (BE CAREFULLY WITH THIS!)

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
ceph_pool_spec.rb: add rspec for ceph::pool

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>