nagios_common: Move checkcommands.cfg into module, from icinga

This will be shared between icinga and shinken now. Also is
no longer a template, since all the templated parts have been
split out into separate files

Change-Id: Iad9e02245bf9309f4c0ff2aefaface6cf13ff0a7
Merge "nagios_common: Move checkcommands.cfg into module, from icinga" into production