[bitnami/chainloop] Add support for usePasswordFiles

[migruiz4]

Description of the change

Adds support for usePasswordFiles and enables it by default.

Benefits

With this change, the chart will mount the secrets as files by default instead of directly setting them into environment variables.

Variables are renamed with the _FILE suffix and point to the mounted secret file.

Possible drawbacks

None

Applicable issues

None

Additional information

N/A

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)

[migruiz4]

Please ignore this PR.

The only password used in the bitnami/chainloop chart is the CONNECTION_STRING variable used in the control-plane-migrations container.

That container uses scratch (no shell) so it is not possible to use $(< to load the env variable from a file.
The binary atlas doesn't support loading the URL from a file, so we need to skip this one.