Solve the original authors' todos

[zadigus]

cf. TODO:

• validate Hasura options e.g. log levels etc
• CORS domains: from ingress routes?
• move configuration (environment variables) into a config-map
• replace {{ .Release.name }}-chartname by {{ $fullname }}
• JWT options: jwk_url, claims_namespace_path, claims_format, audience, issuer. Reflect in HBP as well
  https://hasura.io/docs/1.0/graphql/core/auth/authentication/jwt.html#configuring-jwt-mode
• change way of loading migrations/metadata when helm 3.5 is released (01/2021)
  Allow helm to add external files to chart deployment helm/helm#3276
• helm hooks for migrations/metadata. In particular upgrade/rollback hooks
• handle migrations for multiple databases
• documentation
  • tar -cvf migrations.tar -C migrations .
  • kubectl create configmap migrations --from-file=migrations.tar
  • rm migrations.tar
  • .Values.migrations.configMaps. = { name: migrations, file: migrations.tar }
  • same thing for metadata (except that it accepts only one configmap value)