1. account option `userName` is now allowed by `programs.vdirsyncer`
2. The commented out account option `userNameCommand` was required to be set
by `programs.vdirsyncer` (e.g. as `null`).
It is now disallowed (commented out) by vdirsyncer.
This also adds the modules
- programs.vdirsyncer,
- programs.khal, and
- services.vdirsyncer
that integrate with the new infrastructure.
Co-authored-by: Andrew Scott <3648487+ayyjayess@users.noreply.github.com>
Co-authored-by: Sebastian Zivota <sebastian.zivota@mailbox.org>