Remove tempest/manager.py after 4 year deprecation

tempest/manager.py has been deprecated for over 4 years already,
it's time to remove it.

Implements: blueprint tempest-scenario-manager-stable
Change-Id: Iea813d478a93a1638be597af48929cd50a5e6366
diff --git a/tools/generate-tempest-plugins-list.py b/tools/generate-tempest-plugins-list.py
index 618c388..b449e55 100644
--- a/tools/generate-tempest-plugins-list.py
+++ b/tools/generate-tempest-plugins-list.py
@@ -54,6 +54,9 @@
     'x/kingbird',  # https://bugs.launchpad.net/kingbird/+bug/1869722
     # vmware-nsx is blacklisted since https://review.opendev.org/#/c/736952
     'x/vmware-nsx-tempest-plugin',
+    # mogan is unmaintained now, remove from the list when this is merged:
+    # https://review.opendev.org/c/x/mogan/+/767718
+    'x/mogan',
 ]
 
 url = 'https://review.opendev.org/projects/'