urlaubsverwaltung chart: naming scheme, configurable probes, flexible ingress

- Rename all resources from <chart>-<release>-uv-<kind> to the repo
  standard <release>-<chart>-<kind> (deployment, service, ingress, both
  OnePasswordItem secrets); drop the uv infix. No PVCs in this chart, so
  no storage migration is needed.
- TLS secret renamed to the standard tls-<release>-<chart>-ingress
  (was tls-<chart>-<release>-ingress).
- Probes lifted into values (urlaubsverwaltung.livenessProbe/
  readinessProbe/startupProbe); defaults are exactly the previously
  hardcoded, issue-#9-calibrated settings.
- Repo-standard flexible ingress: ingress.className (default nginx),
  ingress.annotations merged with the cert-manager annotation,
  ingress.enabled flag; domain/clusterIssuer stay required.
- Additive urlaubsverwaltung.env block rendered through tpl with
  value/secretKeyRef/configMapKeyRef forms.
- CI fixtures updated to the new secret names.

Major bump 4.1.2+up6.7.0 -> 5.0.0+up6.7.0 (resource renames).

ci/urlaubsverwaltung/fixtures.yaml

@@ -1,11 +1,11 @@
 # Fixtures for the urlaubsverwaltung install-test: throwaway postgres, a dex
 # OIDC provider (Spring performs OIDC discovery against the issuer at boot)
 # and the secrets the 1Password operator would otherwise materialize.
-# Note: this chart names secrets <chart>-<release>-..., release name is ci.
+# Note: secrets are named <release>-<chart>-..., release name is ci.
 apiVersion: v1
 kind: Secret
 metadata:
-  name: urlaubsverwaltung-ci-uv-db-secret
+  name: ci-urlaubsverwaltung-db-secret
 stringData:
   jdbc-url: jdbc:postgresql://postgres:5432/urlaubsverwaltung
   username: ci
@@ -14,7 +14,7 @@ stringData:
 apiVersion: v1
 kind: Secret
 metadata:
-  name: urlaubsverwaltung-ci-uv-oidc-secret
+  name: ci-urlaubsverwaltung-oidc-secret
 stringData:
   client-id: ci-client
   client-secret: ci-client-secret