[PR #8189/1bbef588 backport][stable-8] Deprecate hipchat callback (#8240)

Deprecate hipchat callback (#8189)

* Deprecate hipchat callback.

* Avoid duplicate 'callback' key.

(cherry picked from commit 1bbef58844)

Co-authored-by: Felix Fontein <felix@fontein.de>

plugins/callback/hipchat.py

@@ -18,6 +18,10 @@ DOCUMENTATION = '''
     description:
       - This callback plugin sends status updates to a HipChat channel during playbook execution.
       - Before 2.4 only environment variables were available for configuring this plugin.
+    deprecated:
+      removed_in: 10.0.0
+      why: The hipchat service has been discontinued and the self-hosted variant has been End of Life since 2020.
+      alternative: There is none.
     options:
       token:
         description: HipChat API token for v1 or v2 API.