(SERVER-1830) Document metrics.conf.
(SERVER-1830) Document metrics.conf.

er0ck/puppetserver,camlow325/puppetserver,er0ck/puppetserver,puppetlabs/puppetserver,puppetlabs/puppet-server,camlow325/puppetserver,camlow325/puppet-server,puppetlabs/puppet-server,camlow325/puppet-server,camlow325/puppetserver,er0ck/puppetserver,camlow325/puppetserver,er0ck/puppetserver,puppetlabs/puppetserver,puppetlabs/puppetserver,camlow325/puppet-server,puppetlabs/puppetserver,puppetlabs/puppet-server