Add night mode (#890)

* Split base template menus out

* Add toggle for night mode setting

* Add vertical flexbox row

Makes each col-* expand to fill the space created by the largest column.

* Use flexbox on main character and group panels

* Fix data table sort control clipping

* Build new css

allianceauth/context_processors.py

@@ -1,7 +1,9 @@
 from django.conf import settings
+from .views import NightModeRedirectView
 
 
 def auth_settings(request):
     return {
         'SITE_NAME': settings.SITE_NAME,
+        'NIGHT_MODE': NightModeRedirectView.night_mode_state(request),
     }