chore: add values file for the stable env of catena-x eV

[ds-asmierzchalski]

Description

With the deployment of the Portal on the stable environment of the association a values file for that environment was added for the dim middle layer like for int.

Why

As for the int environment a values file should be maintained for the stable environment as well to enable an easy deployment of this service.

Issue

Link to Github issue.

Checklist

Please delete options that are not relevant.

• I have performed a self-review of my own code
• I have successfully tested my changes locally
• I have added tests that prove my changes work
• I have checked that new and existing tests pass locally with my changes
• I have commented my code, particularly in hard-to-understand areas
• I have added copyright and license headers, footers (for .md files) or files (for images)

[cla-assistant]

All committers have signed the CLA.