Allow to change the "created"-date via a patch-request

Hi,

I've been moving some of the IMGUR-images (created with MapComplete) towards Panoramax. However, I forgot to add the date of creation.

It seems to not yet be possible to set the 'creation'-date with a patch-request. This would be very useful to fix my error; as editing the database directly is risky and cumbersome; and I'm not gonna re-upload 10K pictures.