[8.x](backport #4292) Add TheHive connector for cases (#4303)

* Add TheHive connector for cases (#4292)

* Add TheHive connector for cases

* Add TheHive connector for serverless cases

* Refresh automated screenshot

* Update docs/en/serverless/cases/manage-cases-settings.mdx

Co-authored-by: DeDe Morton <dede.morton@elastic.co>

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Co-authored-by: DeDe Morton <dede.morton@elastic.co>
(cherry picked from commit 241b955)

# Conflicts:
#	docs/en/serverless/cases/manage-cases-settings.mdx
#	docs/en/serverless/images/observability-cases-add-connector.png

* Delete docs/en/serverless directory

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Co-authored-by: Lisa Cawley <lcawley@elastic.co>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

docs/en/observability/manage-cases-settings.asciidoc

@@ -27,6 +27,7 @@ cases with that system using _connectors_. These third-party systems are support
 * {jira} (including {jira} Service Desk)
 * {ibm-r}
 * {swimlane}
+* TheHive
 * {webhook-cm}
 
 IMPORTANT: To send cases to external systems, you need the appropriate license, and your role must
@@ -43,15 +44,15 @@ After creating a connector, you can set your cases to
 === Create a connector
 
 . From the *Incident management system* list, select *Add new connector*.
-. Select the system to send cases to: *{sn}*, *{jira}*, *{ibm-r}*, *{swimlane}*,
-or *{webhook-cm}*.
+. Select the system to send cases to: *{sn}*, *{jira}*, *{ibm-r}*, *{swimlane}*, *TheHive*, or *{webhook-cm}*.
 
 . Enter your required settings. For connector configuration details, refer to
 {kibana-ref}/resilient-action-type.html[{ibm-r} connector],
 {kibana-ref}/jira-action-type.html[{jira} connector],
 {kibana-ref}/servicenow-action-type.html[{sn-itsm} connector],
 {kibana-ref}/servicenow-sir-action-type.html[{sn-sir} connector],
-{kibana-ref}/swimlane-action-type.html[{swimlane} connector], or
+{kibana-ref}/swimlane-action-type.html[{swimlane} connector], 
+{kibana-ref}/thehive-action-type.html[TheHive connector], or
 {kibana-ref}/cases-webhook-action-type.html[{webhook-cm} connector].
 
 . Click *Save*.