refs #191

refs #181

Until now the show context menu was only displayed when user’s were
visiting routes for that particular show. As we keep a global show
selection state, we can display this context menu at any time, because
the state is not unset when users visit other dashboard sites.

At least for now that makes sense.

This component will help us to outline areas in the dashboard app, that
are scheduled for major overhauls. This should make feedback more
effective as people testing the dashboard can focus their time & effort
on areas that haven’t received the love they deserve.

This refactor includes a bulk of the changes discussed in #181. It
removes the existing navbar and replaces it with a sidebar instead. This
leaves us more room for context-aware navigation options and other
information that is relevant to users.

Additionally, the show management page is now split up into two, the
show episodes management, listing the coming shows/timeslots and the
show’s schedules, and the show basic data page, that contains all mostly
static data for a show and which is usually maintained by
administrators.

refs #181

The show name is displayed in the quick selector and given the changes
proposed as part of #181, it is no longer needed.

This change implements a show overview page with two display modes:
table and grid. Shows can be ordered and searched. Other filters are not
(yet) implemented.

refs #101
refs #181

The AddShowButton was not rendered when the shows weren’t loaded, but
the only requirement for it to render should be if the user is a
superuser.

This component implements the logic for the standard
django-rest-framework (DRF) order parameter.

DRF uses plan field names for ascending and a "-" prefix for descending
order.

Example:
	if you’d want to sort by id you’d write:
		?order=id
	if you’d want to sort by id in reverse order you’d write:
		?order=-id

The OrderFilter supports arbitrary order fields, allows you to set the
sort direction (ascending, descending – configurable per order field)
and supports re-ordering of order fields so that that hierarchical
orders can be set.

This is a helpful ADialog wrapper that manages it’s open state by
itself.

This should make the API functions more accessible for callers as there
won’t be any loose undefined values that were sometimes needed to skip
certain values in certain API endpoints.

Instead, every positional argument is now required and all configurable
options or extensions are part of the options object.

refs #179

refs #179