Zipline chart: ingress standard, secret ref structure (conventions batch 3)

Repo-standard flexible ingress (required clusterIssuer instead of the
hardcoded letsencrypt-issuer, domain moved from config.domain to
ingress.domain, className value, annotations merge, standard TLS secret
name), secrets.<name>SecretRef structure, core secret renamed to the
standard -secret name, additive tpl-rendered env block, documented PVC
naming exception. Major bump 4.1.2+up4.7.0 -> 5.0.0+up4.7.0.

zipline/templates/zipline.pvc.yaml

@@ -1,6 +1,8 @@
 apiVersion: v1
 kind: PersistentVolumeClaim
 metadata:
+  # Documented exception from the "-<kind>" naming scheme (issue #32): renaming
+  # a PVC would provision a new, empty volume, so the historic "-vc" name stays.
   name: {{ .Release.Name }}-{{ .Chart.Name }}-vc
 spec:
   accessModes: