[bitnami/seaweedfs] Add support for PostgreSQL as alternative db

[juan131]

Description of the change

This PR adds support for PostgreSQL as alternative db both as a chart dependency or using an external database. The latter use case was already supported but required extra manual steps that can be now automated using a init-db K8s job.

Benefits

Users can choose between MariaDB or PostgreSQL as the database for Filer metadata.

Possible drawbacks

None

Applicable issues

• fixes [bitnami/seaweedfs] seaweedfs externalDatabase "postgresql" connection error. #29280

Additional information

Installing SeaweedFS using PostgreSQL as a dependency can be achieved installing the chart with the values below:

filer:
  enabled: true
mariadb:
  enabled: false
postgresql:
  enabled: true

In order to use an existing PostgreSQL server and automatically add required db schemas during initialization:

filer:
  enabled: true
mariadb:
  enabled: false
postgresql:
  enabled: false
externalDatabase:
  enabled: true
  store: postgresql
  host: myexternalhost
  port: 5432
  user: myuser
  database: mydatabase
  password: mypassword
  initDatabaseJob:
    enabled: true

Checklist

• Chart version bumped in Chart.yaml according to semver. This is not necessary when the changes only affect README.md files.
• Variables are documented in the values.yaml and added to the README.md using readme-generator-for-helm
• Title of the pull request follows this pattern [bitnami/<name_of_the_chart>] Descriptive title
• All commits signed off and in agreement of Developer Certificate of Origin (DCO)

[juan131]

Please DON'T MERGE until we have finished with internal pipeline required changes

[migruiz4]

Looks good to me!