Drop scheduler services from scheduler nodes

Those nodes only keep the rabbitmq backend now.

The cleanup of those nodes will happen manually.

In another commit, this also migrates the services relying on the saatchi scheduler rpc to now use the ones in the elastic infra.

So we can definitely stop the saatchi rpc services too (and drops all swh references from the scheduler nodes in the clean up phase)

For example, the webapp on moma:

$ bin/octo-diff moma
diff origin/production/moma.softwareheritage.org current/moma.softwareheritage.org
*******************************************
  File[/etc/softwareheritage/deposit/server.yml] =>
   parameters =>
     content =>
      @@ -3,5 +3,5 @@
       scheduler:
         cls: remote
      -  url: http://saatchi.internal.softwareheritage.org:5008/
      +  url: http://scheduler.internal.softwareheritage.org:80/
       storage_metadata:
         cls: remote
*******************************************
  File[/etc/softwareheritage/web/web.yml] =>
   parameters =>
     content =>
      @@ -16,5 +16,5 @@
       scheduler:
         cls: remote
      -  url: http://saatchi.internal.softwareheritage.org:5008/
      +  url: http://scheduler.internal.softwareheritage.org:80/
       counters:
         cls: remote
*******************************************
*** End octocatalog-diff on moma.softwareheritage.org

Refs. swh/infra/sysadm-environment#5035 (closed)