* DEV: Add backend functionality to enable/disable holidays
This will add two backend endpoints, one to disable holidays and
another to enable holidays.
I also introduced a new `Holiday` service that is responsible for
getting the holidays and attaching a new `disabled` attribute to the
holidays. The `#index` action has been updated to use this new service,
so it will return this new `disabled` attribute.
* DEV: Only add enabled holidays to the calendar
I updated this job so that it will use the new `Holiday` service, which
will return the holidays like before but with a new `disabled` field,
which this job will use to only add enabled holidays to the calendar.
* FEATURE: Allow admins to disable/enable holidays
The main thing I added here is a new component `admin-holiday-list-item`
that is responsible for displaying a holiday, and an enable or disable
button and the corresponding functionality.
d31e07c01c