Retire the OpenInfra Labs mailing list

The OpenInfra Labs pilot project was closed down by mutual agreement
of the OpenInfra Foundation and former project contributors[*]. Its
mailing list will no longer be used. Reject any future posts at the
MTA in order to avoid creating the backscatter which would result if
Mailman itself were configured to bounce messages or send notices.

[*] https://lists.opendev.org/archives/list/openinfralabs@lists.opendev.org/thread/FHFSNRS5ZOWW7LJCKSMXT3HVPMSTSUEA/

Change-Id: I40c1568928399e86ac4ab501040ded6874172243

inventory/service/group_vars/mailman3.yaml

@@ -130,6 +130,7 @@ exim_domain_aliases:
   staff@lists.openstack.org: staff@lists.openinfra.dev
   summit-programming-committee@lists.openinfra.dev: summit-track-chairs@lists.openinfra.dev
   summitsponsors@lists.openstack.org: summitsponsors@lists.openinfra.dev
+  openinfralabs@lists.opendev.org: ':fail: this mailing list is not in use'
 mailman_sites:
   # First entry in this list is the primary web domain
   - listdomain: lists.opendev.org
@@ -148,7 +149,7 @@ mailman_sites:
         description: 'Collaborating on Network Based Media Processing related platform and infrastructure systems usage and development.'
         owner: 'ildiko@openstack.org'
       - name: openinfralabs
-        description: 'Discussion of the OpenInfra Labs academic and research resource sharing effort'
+        description: 'No longer active'
         owner: 'mnaser@vexxhost.com'
       - name: rust-vmm
         description: 'Collaborating on Rust-based virtual machine monitors.'