Photos-to-sqlite

- Renamed this project to `dogsheep-photos`. 26
- `apple-photos` command now works even if you haven't yet run `upload`. 19
- `--image-url-prefix` and `--image-url-suffix` options to `apple-photos`. 24
- New `create-subset` command. 23

* Upload photos to S3 in a thread pool 11
* New `--dry-run` option to `upload` command
* New `photos-to-sqlite apple-photos` command for importing Apple Photos metadata 1
* Apple Photos quality scores are imported into `apple_photos_scores` table 15
* Machine learning labels imported from Apple Photos into `labels` table 16

* Only upload photos not already in S3. 9

* First alpha release