graphics/gphoto2: the port had been updated to version 2.5.28

• Stop asking for GNU make, switch to smaller .tar.xz distfile
• Add GitHub CDN as alternative (fallback) download location
• GC no longer needed GNU_CONFIGURE_MANPREFIX and CONFIGURE_ENV
• Install some more of those available documentation files
• Hook the test suite to our framework (sadly, requires GNU sed)

PR: 272433
Reported by: portscout