[bitnami/harbor] Add support for registry storage upload purging setting

[keviiin38]

Description of the change

Add the option to configure of the uploadpurging setting in the registry storage.maintenance section.

Benefits

With this change, the registry could clean the _uploads folders if enabled, which could save a lot of space on the storage backend.

Possible drawbacks

Currently, the value is hardcoded to enabled: false, in order to prevent massive deletes on the storage backend, the default enabled: false has been kept in the values.yaml file.

As opposed to the default values of distribution/distribution which is enabled: true.

Applicable issues

• n/a

Additional information

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)