window: reorganise top and bottom toolbars

This lets users directly launch the calendar dialogue
instead of sidebar in narrow mode.

It moves the view switcher to bottom when narrow.

This also makes the sidebar overlaid for an intermediate
step between narrow and always optionally visible sidebar.

Further, it moves the today button to bottom with the new
navigation button at its old location.

Closes: https://gitlab.gnome.org/GNOME/gnome-calendar/-/issues/1007

Signed-off-by: Markus Göllnitz <camelcasenick@bewares.it>
Part-of: <https://gitlab.gnome.org/GNOME/gnome-calendar/-/merge_requests/542>

src/gui/gui.gresource.xml

@@ -9,7 +9,6 @@
     <file compressed="true">gcal-quick-add-popover.ui</file>
     <file compressed="true">gcal-search-button.ui</file>
     <file compressed="true">gcal-sync-indicator.ui</file>
-    <file compressed="true">gcal-toolbar-end.ui</file>
     <file compressed="true">gcal-weather-settings.ui</file>
     <file compressed="true">gcal-window.ui</file>
   </gresource>