Add dbms.routing.load_balancing.config.server_policies to the configs reference page (#2414)

We state that the _Configuration settings_ page lists all config
settings in Neo4j. But we miss
`dbms.routing.load_balancing.config.server_policies`, which is not a
setting but a setting group. Nevertheless, we need to include this
setting group/plugin on the page.

Author: NataliaIvakina

modules/ROOT/pages/clustering/clustering-advanced/multi-data-center-routing.adoc

@@ -181,8 +181,10 @@ If no rule is able to produce a usable result then the driver is signalled a fai
 === Policy names
 
 The policies are configured under the namespace of the `server_policies` plugin and named as desired.
+You can find them in the _neo4j.conf_ file.
+
 Policy names can contain alphanumeric characters and underscores, and they are case sensitive.
-Below is the property key for a policy with the name `mypolicy`.
+Below is the property key for a policy with the name `mypolicy`:
 
 `dbms.routing.load_balancing.config.server_policies.mypolicy=`
 

modules/ROOT/pages/configuration/configuration-settings.adoc

@@ -6,6 +6,8 @@
 The Neo4j configuration settings are set in xref::/configuration/file-locations.adoc[_neo4j.conf_].
 Refer to xref:configuration/neo4j-conf.adoc#_configuration_settings[The neo4j.conf file] for details on how to use configuration settings.
 
+To list all available configuration settings on a Neo4j server, run the link:https://neo4j.com/docs/cypher-manual/5/clauses/listing-settings[`SHOW SETTINGS`] command.
+
 
 == Dynamic configuration settings
 
@@ -28,6 +30,42 @@ It is recommended that the settings for a database are the same across all membe
 For more information on how to update dynamic configuration settings, see xref:configuration/dynamic-settings.adoc[Update dynamic settings].
 
 
+[role=label--enterprise]
+== Configuration setting group
+
+When deploying a multi-data cluster in Neo4j, you can configure the load balancing framework.
+
+In Neo4j, the load balancing system is based on a plugin architecture.
+The primary built-in plugin is `server_policies`, which is set up by the following property:
+
+[source, shell]
+----
+dbms.routing.load_balancing.plugin=server_policies
+----
+
+`server_policies` plugin determines which servers are eligible to serve client requests based on predefined routing policies.
+If a client does not specify a routing policy, the system defaults to using all available servers.
+
+You can define routing policies by using the following property format:
+
+[source, shell]
+----
+dbms.routing.load_balancing.config.server_policies.<policy-name>=<policy-definition>
+----
+
+Where `<policy-name>` is the name of the routing policy, and `<policy-definition>` specifies the server selection logic.
+
+For the default policy, the `default` policy name is reserved.
+Its default value is `all()`:
+
+[source, shell]
+----
+dbms.routing.load_balancing.config.server_policies.default=all()
+----
+
+See xref:clustering/clustering-advanced/multi-data-center-routing.adoc#mdc-load-balancing-framework[Clustering -> Multi-data center routing] for more details.
+
+
 == Checkpoint settings
 
 Checkpointing is the process of flushing all pending page updates from the page cache to the store files.