[DOCS|Management] Added page for License Management] (#19220) (#19277)

* [DOCS|Management] Added page for License Management]

* [DOCS|Management] Updated license management docs per review comments

* [DOCS|Management] More review comments on license management doc

docs/management.asciidoc

@@ -13,6 +13,8 @@ This section is pluginable, so in addition to the out of the box capabitilies,
 packs such as {xpack} can add additional management capabilities to Kibana.
 --
 
+include::management/managing-licenses.asciidoc[]
+
 include::management/index-patterns.asciidoc[]
 
 include::management/managing-fields.asciidoc[]

docs/management/managing-licenses.asciidoc

@@ -0,0 +1,23 @@
+[[managing-licenses]]
+== License Management
+
+When you install Kibana, it generates a Basic license
+with no expiration date.  To start a 30-day trial,
+view the status of your license, or install a new license
+go to *Management* and click *License
+Management*.
+
+[role="screenshot"]
+image::images/management-license.png[]
+
+The 30-day trial enables you to try out the full set of
+https://www.elastic.co/subscriptions[Platinum features],
+including security, machine learning, alerting, graph capabilities,
+and more.
+
+At the end of the trial period, your license reverts
+to a Basic license. To continue using the Platinum features,
+purchase a subscription and update your license.
+
+For a comparison of the Elastic license levels,
+see https://www.elastic.co/subscriptions[the subscription page].