Draft: "git annex mode": enable writing metadata alongside immutable symlinks
This hopefully fixes https://bugs.kde.org/show_bug.cgi?id=415949
To recap: git annex stores raw files as symlinks to an immutable directory (good, my RAWs won't change), with *.xmp stored as normal files (tracked by ye olde git). Digikam should be able to write to e.g. library/IMG0002.CR2.xmp, but refuses to as library/IMG0002.CR2 is an immutable symlink. Digikam correctly reads metadata in this case, and will write to it if one does git annex unlock library/IMG0002.CR2
(which replaces the symlink with a copy of the immutable content, i.e. makes the situation "normal").
Best, Kevin