Change server_puppetserver_metrics default to true

The default in Puppetserver is actually `true`, not `false`.

(IMO, `server_puppetserver_metrics` isn't a great parameter name as its
actual purpose is to configure whether http client metrics are
collected, and has no impact on the much greater number of other metrics
still collected when this is set to `false`.)

manifests/init.pp

@@ -439,7 +439,7 @@
 #                                           Defaults to 30000, using the Jetty default of 30s
 #
 # $server_puppetserver_metrics::            Enable puppetserver http-client metrics
-#                                           Defaults to false because that's the Puppet Inc. default behaviour.
+#                                           Defaults to true because that's the Puppet Inc. default behaviour (since Puppetserver 5.0.0).
 #
 # $server_puppetserver_profiler::           Enable JRuby profiling.
 #                                           Defaults to true because that's the Puppet Inc. default behaviour (since Puppetserver 5.0.0).
@@ -708,7 +708,7 @@
   Boolean $server_environment_class_cache_enabled = $puppet::params::server_environment_class_cache_enabled,
   Boolean $server_allow_header_cert_info = $puppet::params::server_allow_header_cert_info,
   Integer[0] $server_web_idle_timeout = $puppet::params::server_web_idle_timeout,
-  Boolean $server_puppetserver_metrics = false,
+  Boolean $server_puppetserver_metrics = true,
   Boolean $server_puppetserver_profiler = true,
   Boolean $server_metrics_jmx_enable = $puppet::params::server_metrics_jmx_enable,
   Boolean $server_metrics_graphite_enable = $puppet::params::server_metrics_graphite_enable,