Sort by name/date in events overview admin

One-sentence description

Sort by date in events overview admin

Desired behaviour

The events in the admin overview (/admin/events) are sorted by id by default. Since we have overridden the event name, date and registration start columns for them to be a link and contain the week day respectively these are not sortable automatically anymore.

This could be solved by adding the admin_order_field attribute:

    def colored_first_name(self):
        return format_html(
            '<span style="color: #{};">{}</span>',
            self.color_code,
            self.first_name,
        )

    colored_first_name.admin_order_field = 'first_name'

• Overview link: title (if possible due to translation)
• Date: start
• Registration start: registration_start