devel/datovka: update to 4.22.1

While here move to mail category. It was wrongly placed under devel in PR 267597

ChangeLog: https://gitlab.nic.cz/datovka/datovka/-/blob/develop/ChangeLog

• Viewing number of recently unread messages in top node description when top node collapsed in account list. Also changed the icon for the top node.

PR: 271005 267597
Reported by: 000.fbsd@quip.cz
Approved by: freebsd@sysctl.cz (maintainer)