[DOCS] Remove X-Pakc installation page (elastic/x-pack-elasticsearch#4416)

Original commit: elastic/x-pack-elasticsearch@a5ca5c7230

docs/en/setup/installing-xes.asciidoc

@@ -1,9 +0,0 @@
-[role="xpack"]
-[[installing-xpack-es]]
-== Installing X-Pack in Elasticsearch
-++++
-<titleabbrev>Installing {xpack}</titleabbrev>
-++++
-
-By default, when you install {es}, {xpack} is installed. See
-<<install-elasticsearch>>.

docs/en/setup/setup-xes.asciidoc

@@ -4,10 +4,16 @@
 
 [partintro]
 --
-{xpack} is an Elastic Stack extension that bundles security, alerting,
-monitoring, reporting, machine learning, and graph capabilities.
+{xpack} is an Elastic Stack extension that provides security, alerting,
+monitoring, reporting, machine learning, and many other capabilities. By default, 
+when you install {es}, {xpack} is installed. 
+ 	 
+If you want to try all of the {xpack} features, you can 
+{xpack-ref}/license-management.html[start a 30-day trial]. At the end of the 
+trial period, you can purchase a subscription to keep using the full 
+functionality of the {xpack} components. For more information, see 
+https://www.elastic.co/subscriptions.
 
-* <<installing-xpack-es>>
 * <<configuring-monitoring>>
 * <<configuring-security>>
 * <<setup-xpack-client>>
@@ -16,7 +22,6 @@ monitoring, reporting, machine learning, and graph capabilities.
 
 --
 
-include::installing-xes.asciidoc[]
 include::{xes-repo-dir}/monitoring/configuring-monitoring.asciidoc[]
 include::{xes-repo-dir}/security/configuring-es.asciidoc[]
 include::setup-xclient.asciidoc[]