feat(template): update docker registry

[YaRissi]

Changes

• Update docs link to new destination
• Automate password creation with magic variables
• Add docker registry template to service model

[github-actions]

Hi @YaRissi! 👋

It appears to us that you are either adding a new service or making changes to an existing one.
We kindly ask you to also review and update the Coolify Documentation to include this new service or it's new configuration needs.
This will help ensure that our documentation remains accurate and up-to-date for all users.

Coolify Docs Repository: https://github.com/coollabsio/coolify-docs
How to Contribute a new Service to the Docs: https://coolify.io/docs/get-started/contribute/service#adding-a-new-service-template-to-the-coolify-documentation