Allow adding photos to an AED being added, not just to existing ones

[RicoElectrico]

Feels like an oversight 😅 However, the current API requires node ID which is not present at the upload stage. This would mean splitting the upload into 3 parts: uploading a node to the OSM API to get the ID, adding a photo to our backend and then editing the node to include the image=* tag. (the last happens on the backend). This feels extremely flimsy.

Maybe we could just make the backend upload the AED on behalf of the user? To be stateless, ditch the changeset opening and just use 1 changeset per AED. Not optimal, but nobody will use our page to bulk load AEDs.