Places sidebar is a widget that enabled the user to select
XDG directories, bookmarks and mounted network locations,
as well as manages permanent and removable devices.
The new design that aims to look less clutered makes the
sidebar display only removable devices, as well as mounted
networks, bookmarks and XDG directories, and delegates the
management of permanent devices such as hard drive partitions
to GtkPlacesView, a newly introduced widget for this specific
purpose.
To delegate it, add an "Other Locations..." item to notify
when the permanent devices manager is required. Besides that,
don't show these fixes devices on the sidebar itself, as they
are not supposed to be handled by the sidebar anymore.
https://bugzilla.gnome.org/show_bug.cgi?id=752034
The places sidebar already does all the work to determine the
right label to use for the current location of the filechooser.
We want to use the same label in the headerbar subtitle, so
add some private API to get it.
We were using GTkTreeView in a simple list. Also, as we know,
GtkCellRenderers are not the best way to theme and manipulate
widgets.
So instead use a GtkListBox to modernize the GtkPlacesSidebar,
and in the way clean up some parts of the code (like headings)
which were not used anymore.
Also we don't use a model anymore, since the data is simple
enough to manage it in a subclass of the row itself.
