This commit introduces a new web_editor UserValueWidget on the
we-imagepicker tag, this widget allows the user to pick an image or a
video using the MediaDialog, and calls the containing snippet option's
method (specified via data-attribute) with the url of the chosen picture
or video as widgetValue. Videos are disabled by default and can be
accessed through the use of the data-allow-videos="selector" data
attribute, any $target that matches the selector will have videos
available in the media dialog.
Part of odoo/odoo#41561
task-2155808