Add summit-track-chairs ML in place of old name

The OpenInfra Summit organizers have decided they're going back to
using the term "track chairs" instead of "programming committee" and
would like to switch to a new mailing list name in order to
coordinate things for the upcoming conference. Remove the old list
from our configuration when adding the new one, and set up a
forwarding alias for the old list's address so that replies to
previous messages will end up in the right place.

Change-Id: I8060b78b74f66dd8eb95d83659cc92b3186f573e

inventory/service/host_vars/lists.openstack.org.yaml

@@ -40,6 +40,7 @@ exim_domain_aliases:
   goldmembers@lists.openstack.org: goldmembers@lists.openinfra.dev
   marketing@lists.openstack.org: marketing@lists.openinfra.dev
   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
 exim_routers:
   - mailman_verp_router: |
@@ -231,8 +232,8 @@ mailman_sites:
         description: 'Private list for OpenInfra Foundation staff members'
         admin: 'jeremy@openinfra.dev'
         password: "{{ mailman_list_password }}"
-      - name: summit-programming-committee
-        description: 'OpenInfra Summit programming committee communications'
+      - name: summit-track-chairs
+        description: 'OpenInfra Summit track chair communications'
         admin: 'erin@openinfra.dev'
         password: "{{ mailman_list_password }}"
       - name: summitsponsors