More support for the medium of film#604

Film is a medium. Digital is a medium. Film is not a category.

Please add metadata level support to tag a photo’s capture medium. Fim or Digital (or Paper etc.), with the default being digital, as I’m sure there are may orders of magnitude more of those.

Remove Film as a category, so we can use three categories for film photos :-)

Also please add suport for film stocks in the metadata. There are likely fewer of those than cameras, or lenses.

<3