Adds a command to reorganize a folder of photos, renaming them so that
they contain date and time so that they're sorted by that.
This also renames files associated with the photos, like the
descriptions, like IMG_1234.jpg with IMG_1234.md
Just what the world needs, another silly Rust re-write! But it was a good exercise in learning.
There's a lot of messy things, which is why this is 0.2.0-pre.1. Going to make some cleaning passes after landing this.
