Add photographers credits

[dsluijk]

Add the ability to credit photographers for a specific album.

• It must be possible to credit multiple photographers.
• Photographers should be stored in a separate table so they can be updated centrally.
• It should be possible to link to the photographers portfolio.
• It could be possible to add a photo for a photographer.
• It might be possible for a photographer to get edit rights for the albums they are linked to.
• It shouldn't be a requirement that a photographer is credited.