sysutils/packer: Update 1.10.1 => 1.16.0

Port changes:

• Define LICENSE=BSL11 (custom) to satisfy check-sanity.
• Pet portlint (use tab instead of spaces).
• Use DISTVERSION instead of PORTVERSION.

Changelog:
https://github.com/hashicorp/packer/blob/v1.16.0/CHANGELOG.md

PR: 297515
Reported by: Brad Ackerman <brad@facefault.org> (maintainer)
Approved by: osa, vvd (Mentors, implicit)