[scheduler][joy] Add event editing inside a popover

[flaviendelangle]

Follow up on #17702

Add a basic UI to edit the event properties.
This will be enriched as we add new properties to the event.

In this PR:

• Open a Popover created with Base UI when the user click on an event (we can move to double click later or an a detail Popover before the editing one in the future)
• Add a field to edit at start date-time and end date-time (use browser input for now and parse the value, one input for date one input for time)
• Add a field to change the name of the event
• Add a field to change the description of the event (no need for Rich Text Editor for now)

Not in this PR: