Started fetching some variables from os::params

Signed-off-by: Samuli Seppänen <samuli.seppanen@gmail.com>
Made monit start/stop rules OS-agnostic

Note that monit rules won't work for Fedora, because it does not have a single
service script which could be used to manage the OpenVPN instances, and it does
not respect wildcards. In addition, variables defined in defined types are
impossible to access outside them (e.g. from templates).

Signed-off-by: Samuli Seppänen <samuli.seppanen@gmail.com>