Add gitweb lister pod

make helm-diff is ok but shows too much since production and staging are a bit diverged currently (so not shown here)

Refs. swh/infra/sysadm-environment#4984 (closed)

Depends on !93 (merged)

swh/values/staging.yaml

@@ -113,6 +113,11 @@ listers:
       - swh.lister.golang.tasks.IncrementalGolangLister
       autoScaling:
         maxReplicaCount: 1
+    gitweb:
+      queues:
+      - swh.lister.gitweb.tasks.GitwebListerTask
+      autoScaling:
+        maxReplicaCount: 1
     launchpad:
       queues:
       - swh.lister.launchpad.tasks.FullLaunchpadLister