Unify OS specific munin-conf.conf

In essence all munin-node.conf files contained the same template,
besides a few values. By moving all to a single template, maintenance
burden is reduced. To ensure all values are still present in the
templates, tests are added.
Unify logrotate files into templates
Remove useless files
Merge pull request #30 from oxilion/file-cleanup

Clean up files by using templates