[IMP] web_editor: improve image optimization workflow in media dialog

Previously, when selecting an image, the user could optimize their
images by clicking a little cog icon in the media dialog. They would
also be prompted to optimize their images when uploading them. In most
cases, it makes a lot more sense to always save the original in the
database, and optimize the original whenever it's dropped in the page
automatically.

A second problem is that when using the optimization feature, optimized
images would be displayed along the originals by default, resulting in a
lot of duplicates while browsing the media dialog.

This commit changes both of these things:

- By default, when uploading an image, the original uploaded image is
  used. The user can still optimize their image manually through the
  media-dialog by using the cog icon. When choosing an image in the
  media-dialog, if it's not already an optimized image, an optimized copy
  is automatically created and used instead.

- Optimized images are now hidden by default, in the media dialog, and
  can be shown by clicking a checkbox at the top of the modal when in
  debug mode

task-2091417
closes odoo/odoo#45174

addons/web_editor/controllers/main.py

@@ -173,7 +173,16 @@ class Web_Editor(http.Controller):
         if attachment.type == 'url':
             raise UserError(_("You cannot change the quality, the width or the name of an URL attachment."))
         if copy:
+            original = attachment
             attachment = attachment.copy()
+            attachment.original_id = original
+            # Uniquify url by adding a path segment with the id before the name
+            if attachment.url:
+                url_fragments = attachment.url.split('/')
+                url_fragments.insert(-1, str(attachment.id))
+                attachment.url = '/'.join(url_fragments)
+        elif attachment.original_id:
+            attachment.datas = attachment.original_id.datas
         data = {}
         if name:
             data['name'] = name