Improve image edit form

[rolandgeider]

At the moment, when users submit a new exercise, they can also upload images. In this case they are presented with this form:

However, it's later not possible to edit these values:

It would be nice if we could re-use the form from the submission process to allow admins to edit these values. Newly added images for existing exercises should also show the form (this would make it possible to implement #2184

[lvdwijngaart]

Heyhey, we started on this issue and we're far enough to where were confident we can implement this. Right now we abstracted the modal that lets you add an image from Step5Images.tsx into an ImageFormModal component file. This can be used by Step5Image.tsx as an add image form, and can be opened when clicking an edit button in the ImageCard (card as seen in the second picture in this issue's post) as an edit image form.

What is still left to be done is make sure that the edit modal sends the new values as an Update operation to the backend and write the relevant testcases.

I'm not sure what the guidelines are here but wanted to give an update and show that we are able to implement this so we can be assigned to this issue.

[rolandgeider]

awesome!

(also, there are no real guidelines, I'll just assign you)