Add mention of reusable integration policies (#1492)

* Add mention of reusable integration policies

* Update agent-policies.asciidoc

* Update add-integration-to-policy.asciidoc

(cherry picked from commit e5dd5ef)

Author: kilfoyle

docs/en/ingest-management/agent-policies.asciidoc

@@ -158,6 +158,9 @@ Also see <<create-a-policy-no-ui>>.
 == Add an integration to a policy
 
 An {agent} policy consists of one or more integrations that are applied to the agents enrolled in that policy.
+When you add an integration, the policy created for that integration can be shared with multiple {agent} policies.
+This reduces the number of integrations policies that you need to actively manage.
+
 To add a new integration to one or more {agent} policies:
 
 . In {fleet}, click **Agent policies**.

docs/en/ingest-management/integrations/add-integration-to-policy.asciidoc

@@ -6,6 +6,9 @@
 ++++
 
 An <<agent-policy,{agent} policy>> consists of one or more integrations that are applied to the agents enrolled in that policy.
+When you add an integration, the policy created for that integration can be shared with multiple {agent} policies.
+This reduces the number of integrations policies that you need to actively manage.
+
 To add a new integration to one or more {agent} policies:
 
 . In {kib}, go to the **Integrations** page.