waiverdb: Set fixed number of processes ans threads

New waiverdb container image starts 8 gunicorn web worker processes by
default using WEB_CONCURRENCY environment variable. This causes memory
to spike (over 500MiB) and workers to get terminated.

Instead of increasing memory limits, a better solution is to decrease
the number of processes and increase number of threads since the app
mostly waits on DB requests to finish and waiverdb workers themselves
are thread-safe.

roles/openshift-apps/waiverdb/templates/deploymentconfig.yml

@@ -60,6 +60,11 @@ spec:
           mountPath: /etc/fedora-messaging
           readOnly: true
         env:
+        - name: GUNICORN_CMD_ARGS
+          value: >-
+            --workers=3
+            --threads=6
+            --timeout=90
         - name: DATABASE_PASSWORD
           valueFrom:
             secretKeyRef: