Exif 3.0 support

[kmilos]

See e.g. https://iptc.org/news/exif-3-0-released-featuring-utf-8-support/

• Add basic UTF-8 type #2740
• Add new Exif 3.0 tags #2661
• Update changed tag descriptions if needed
• JUMBF support (separate feature?)

[clanmills]

Groan.... Looks like lots of work ahead. I'm happy to be retired!

[luzpaz]

@kmilos do you mind appending the PRs associated with the list items in the OP ?

[luzpaz]

Note: downstream Gnome Shotwell referenced this ticket: https://gitlab.gnome.org/GNOME/shotwell/-/issues/5065

[kmilos]

@luzpaz Done.

Note that I'm not actively working on the UTF-8 type support, anyone is welcome to take over.