First cut at a photo migrator old-embed -> hecuba.

Still has some issues, but the bones are there.

It seems that some of the paths in the existing data are invalid.

e.g.

select id, photos from entities where
id='adce5e2650f7532e26b969a3f8743fab3df7cadd';

the path to the photo doesn't exist.
We should get these from environment variables as a rule to keep us from wanting to put them in code.