[DOCS] Relocate "Plugins" page (#54974) (#57420)

Author: jrodewig

docs/reference/index.asciidoc

@@ -16,12 +16,6 @@ include::getting-started.asciidoc[]
 
 include::setup.asciidoc[]
 
-include::setup/setup-xes.asciidoc[]
-
-include::setup/setup-xclient.asciidoc[]
-
-include::setup/bootstrap-checks-xes.asciidoc[]
-
 include::upgrade.asciidoc[]
 
 include::aggregations.asciidoc[]

docs/reference/modules.asciidoc

@@ -46,10 +46,6 @@ The modules in this section are:
 
     A Java node client joins the cluster, but doesn't hold data or act as a master node.
 
-<<modules-plugins,Plugins>>::
-
-    Using plugins to extend Elasticsearch.
-
 <<modules-threadpool,Thread pools>>::
 
     Information about the dedicated thread pools used in Elasticsearch.
@@ -83,8 +79,6 @@ include::modules/network.asciidoc[]
 
 include::modules/node.asciidoc[]
 
-include::modules/plugins.asciidoc[]
-
 include::modules/threadpool.asciidoc[]
 
 include::modules/transport.asciidoc[]

docs/reference/modules/plugins.asciidoc

@@ -1,12 +1,13 @@
 [[modules-plugins]]
 == Plugins
 
-[float]
-=== Plugins
-
 Plugins are a way to enhance the basic Elasticsearch functionality in a
 custom manner. They range from adding custom mapping types, custom
 analyzers (in a more built in fashion), custom script engines, custom discovery
 and more.
 
-See the {plugins}/index.html[Plugins documentation] for more.
+For information about selecting and installing plugins, see
+{plugins}/index.html[{es} Plugins and Integrations].
+
+For information about developing your own plugin, see
+{plugins}/plugin-authors.html[Help for plugin authors].

docs/reference/setup.asciidoc

@@ -95,4 +95,12 @@ include::setup/stopping.asciidoc[]
 
 include::setup/add-nodes.asciidoc[]
 
-include::setup/restart-cluster.asciidoc[]
+include::setup/restart-cluster.asciidoc[]
+
+include::setup/setup-xes.asciidoc[]
+
+include::setup/setup-xclient.asciidoc[]
+
+include::setup/bootstrap-checks-xes.asciidoc[]
+
+include::modules/plugins.asciidoc[]