EZP-23748: As an editor, I want to be able to fill the image field

JIRA: https://jira.ez.no/browse/EZP-23748

# Description

This PR adds a field edit view for the Image fields, as a result it's not possible to handle the Image fields content.

Screencast: https://www.youtube.com/watch?v=GuGH5TrmAQU

## Bug / Known limitations

* [No drag and drop yet](https://jira.ez.no/browse/EZP-23789) (to limit the size of this already too big PR)
* Because of [EZP-23788](https://jira.ez.no/browse/EZP-23788), you can not update the alternative text without updating the image
* The image type is not displayed if the image field is already filled because [the REST API does not provide the mime type of the image](https://jira.ez.no/browse/EZP-23758).
* In an ideal world, [the chosen file should uploaded as soon as possible](https://jira.ez.no/browse/EZP-23802) (for instance while the user is filling the rest of the form) but [the REST API is missing a resource for that](https://jira.ez.no/browse/EZP-23801).

## Tasks

* [x] Implement a basic Image field edit view
* [x] Avoid sending the image content even if it was not changed
* [x] Improve the CSS to better handle small images (width < 300px)
* [x] Improve the transitions to make it feel smoother
* [x] Fix the form validation so that the form is updated when the user clicks on publish
* [ ] ~~Drag an drop~~ (will be done later in https://jira.ez.no/browse/EZP-23789)

# Tests

unit tests + manual test
I'll always prefer code clarity to complexity, and especially since the CSS minifier will do the best choice from size point of view. (and after the gzip compression, the size difference will be completely irrelevant anyway).