feat(helm): add all missing env vars from README to Helm chart

Add TZ, LOG_LEVEL, FORCE_HTTPS, TRUST_PROXY, OIDC_ISSUER, OIDC_CLIENT_ID,
OIDC_DISPLAY_NAME, OIDC_ONLY, OIDC_ADMIN_CLAIM, OIDC_ADMIN_VALUE, OIDC_SCOPE,
DEMO_MODE to values.yaml and configmap.yaml. Add OIDC_CLIENT_SECRET as a
secretEnv entry rendered in secret.yaml and mounted in deployment.yaml.

chart/templates/deployment.yaml

@@ -54,6 +54,12 @@ spec:
                   name: {{ default (printf "%s-secret" (include "trek.fullname" .)) .Values.existingSecret }}
                   key: ADMIN_PASSWORD
                   optional: true
+            - name: OIDC_CLIENT_SECRET
+              valueFrom:
+                secretKeyRef:
+                  name: {{ default (printf "%s-secret" (include "trek.fullname" .)) .Values.existingSecret }}
+                  key: OIDC_CLIENT_SECRET
+                  optional: true
           volumeMounts:
             - name: data
               mountPath: /app/data