feat: build desired photo-api-base image and only amd64

Recent updates to Photo API build (https://gitlab.developers.cam.ac.uk/uis/devops/iam/identity-photos-service/photo-api/-/merge_requests/130) have had to update to dlib==19.24.6 so make that here.

Once built, Photo API build will then need to be told to use it. Actual photo-api build is currently using old (pre-dlib pinning) registry image.