Feature: adding holidays and vacantion periods

[landonreed]

Issue by skinkie Thursday Jul 12, 2018 at 10:47 GMT Originally opened as https://github.com/catalogueglobal/datatools-ui/issues/220

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For many countries holidays are important exception days that usually force a schedule to to change from a weekday to a Sunday. Instead of adding them per feed, it would be convenient to have them predefined somewhere so they can be applied on every feed as exceptions.

Similarly vacation periods sometimes mean a reduction in service, you might want to defined the know vacantion periods outside the scope of the different feeds.