SYS-677 radicale helm chart - CalDAV / CardDAV server

[instantlinux]

Summary of Changes

Add a new helm chart - radicale. This supports CalDAV / CardDAV functionality better than its rivals, for a couple of reasons: the newest version (since April 2026) supports calendar-sharing out of the box, and the code maintainer publishes a docker image with each new version.

Also:

• address a few more ansible deprecations in the docker_node and kubernetes roles. Ansible is still as horrendous as ever, with its treadmill of gratuitous breaking changes.
• bump vaultwarden version to 1.37.1 - the vendor still doesn't provide a version-compatibility error message, and according to google "an infinite loading screen or skeleton state can happen due to a client-server version mismatch", so check the vaultwarden version anytime the extension craps out like that.

Why is this change being made?

Nextcloud is long in the tooth, unwieldy to operate, and difficult to update once its database or file storage gets out of sync. This helm chart is one of three to be implemented here to replace its core features: immich, radicale and an upcoming apache-webdav server.

How was this tested? How can the reviewer verify your testing?

Manual testing.

Completion checklist

• The pull request is linked to all related issues
• This change has unit test coverage
• Documentation has been updated
• Dependencies have been updated and verified