Improved class documentation

Signed-off-by: Samuli Seppänen <samuli@openvpn.net>
Explicitly include params.pp in monit.pp

If mysql::monit is cherry-picked to a node then it won't find mysql::params
unless the latter is explicitly loaded.

Signed-off-by: Samuli Seppänen <samuli@openvpn.net>