view: Remove first weekday helpers when unecessary

Not all views need to know the first weekday, and those
who need, it can be stored internally.

src/views/gcal-week-header.c

@@ -1671,7 +1671,7 @@ gcal_week_header_init (GcalWeekHeader *self)
   self->selection_start = -1;
   self->selection_end = -1;
   self->dnd_cell = -1;
-  self->weather_service = NULL;
+  self->first_weekday = get_first_weekday ();
 
   gtk_widget_init_template (GTK_WIDGET (self));
 
@@ -1823,15 +1823,6 @@ gcal_week_header_set_manager (GcalWeekHeader *self,
                             self);
 }
 
-void
-gcal_week_header_set_first_weekday (GcalWeekHeader *self,
-                                    gint            nr_day)
-{
-  g_return_if_fail (GCAL_IS_WEEK_HEADER (self));
-
-  self->first_weekday = nr_day;
-}
-
 void
 gcal_week_header_add_event (GcalWeekHeader *self,
                             GcalEvent      *event)