sysutils/zelta: Add new port

Zelta is a suite of tools offering a streamlined approach to managing
ZFS snapshot replication across systems. It's built with the intention
of simplifying complex ZFS functions into safe and user-friendly
commands while also being the foundation for large-scale backup and
failover environments. It's easy and accessible while working with most
UNIX and UNIX-like base systems without additional packages. It's
optimized for environments with strict permission separation, and
integrates well into many types of existing ZFS workflows.

PR: 278582
Sponsored by: Bell Tower Integration
Sponsored by: Klara, Inc.
Co-authored-by: JT Pennington <jt.pennington@klarasystems.com>