[enh] configurable default interface locale - #177

searx/settings.yml

     https_rewrite : True # Force rewrite result urls. See searx/https_rewrite.py
     useragent_suffix : "" # suffix of searx_useragent, could contain informations like an email address to the administrator
     image_proxy : False # Proxying image results through searx
+    default_locale : "" # Default interface locale - leave blank to detect from browser information
 
 engines:
   - name : wikipedia

searx/webapp.py

 def get_locale():
     locale = request.accept_languages.best_match(settings['locales'].keys())
 
+    if settings['server'].get('default_locale'):
+        locale = settings['server']['default_locale']
+
     if request.cookies.get('locale', '') in settings['locales']:
         locale = request.cookies.get('locale', '')