Gets a list of EPG Slots in the channel with EPG Programmes.
Supports searching using ?slots__between=<start_date>,<end_date>, which will
return all slots between those times, including slots that start before or end
after the given window. In other words, it also includes slots in progress
during the given time window.
It is also possible to use ?announcedbetween, which does the same thing than
?slotsbetween but with announced times instead of actual start time.