fix(translations): remove old translation files and merge redundant files (#1370)

* fix(locale): Remove old translation files introduced by weblate

The updated translation files are already available in the new `enext`
system under `app/eventyay/locale`.

* fix(locale): Merge redundant language files

Author: Sak1012

app/eventyay/config/settings.py

@@ -571,7 +571,7 @@ def instance_name(request):
         'natural_name': 'Deutsch',
         'official': True,
         'percentage': 100,
-        'path': 'de_DE',
+        'path': 'de',
     },
     'de-formal': {
         'name': _('German (formal)'),
@@ -618,7 +618,7 @@ def instance_name(request):
         'natural_name': 'Français',
         'official': False,
         'percentage': 98,
-        'path': 'fr_FR',
+        'path': 'fr',
     },
     'it': {
         'name': _('Italian'),