net-mgmt/zabbix44-*: Mark as deprecated

Mark as deprecated due to being marked end of life upstream.

Stable release: Zabbix 4.4
Release date: Q3, 2019
End of Full Support: Q1, 2020
End of Limited Support: Q2, 2020

PR: 250779
Approved by: Pakhom Golynga <pg@pakhom.spb.ru> (maintainer)