graphics/airsaned: New port: Apple AirScan compatible SANE web frontend

A SANE WebScan frontend that supports Apple's AirScan protocol.
Scanners are detected automatically, and published through mDNS.
Acquired images may be transferred in JPEG, PNG, and PDF/raster format.

WWW: https://github.com/SimulPiscator/AirSane

PR: 242144
Approved by: arrowd (mentor)
Differential Revision: https://reviews.freebsd.org/D32314