Close modals with ESC key

[verheyenkoen]

Enhancement

Allow modal popups to be closed by hitting the ESC key on the keyboard.

Expected behavior

TBD:

• [ ] Modal popups will close when the user hits the ESCAPE key, mimicking the cancel button behaviour.
• [ ] If a model contains form fields*, should we track the "dirty state" of the form and warn if they will close a dirty form?
• [ ] If so, should we also do this when they try to close a "dirty" popup using the "Cancel" button?
• [ ] As an alternative we could also only activate the ESCAPE hotkey when modal popups don't contain any form fields.

(*) Important! Modal popups containing form fields don't necessary contain a <form> element as HTMX can collect form values via a custom selector via hx-include.

Note: since a redesign is upcoming, maybe we won't have any forms left in modal popups (only confirm/error dialogs) so this behaviour would only be temporary. In that case we can probably ignore the dirty check, or have this ticket on hold until after the redesign.

[mietcls]

Thank you for this recap. Seems like a good idea to wait until we have done the redesign, so we don't surprise people with unexpected behaviour and wind up fixing the dirty state anyways.