Payments add modal form

* adds help texts to add payment form
* adds removing button for payments
* refactors user fetching into BaseForm
* adds generic RemoveModalForm which is intended to be used for every modal form which shall remove something
* adds translations
* removes unused html
* prepares payment amount field to be able to process german inputs like '1.000,50' which is not the international default

konova/sub_settings/django_settings.py

@@ -53,6 +53,7 @@ INSTALLED_APPS = [
     'django.contrib.messages',
     'django.contrib.staticfiles',
     'django.contrib.gis',
+    'django.contrib.humanize',
     'simple_sso.sso_server',
     'django_tables2',
     'bootstrap_modal_forms',
@@ -143,9 +144,12 @@ AUTH_PASSWORD_VALIDATORS = [
 # Internationalization
 # https://docs.djangoproject.com/en/3.1/topics/i18n/
 
-LANGUAGE_CODE = 'en-us'
+LANGUAGE_CODE = 'de'
+
+USE_THOUSAND_SEPARATOR = True
 
 DEFAULT_DATE_TIME_FORMAT = '%d.%m.%Y %H:%M:%S'
+DATE_FORMAT = '%d.%m.%Y'
 
 TIME_ZONE = 'Europe/Berlin'