Block creating any new elements outside of images in the API

Bastien Abadie
2022-05-06T10:12:56Z

Refs https://gitlab.com/arkindex/backend/-/issues/168

This one is easier than the second about blocking outside of parents.

Every endpoint that allows element creation and update should check that the coordinates are not outside of the image:

CreateElement

CreateElements

(Partial)UpdateElement

A 400 should be raised immediately when the user submits an invalid polygon