Use human readable date

For DoB and DoD, wikipedia use a non standard ISO format, not easily readable.
Now the date is displayed in an human readable form, using the language setting as locale if available. If not, it uses the default locale.

searx/engines/wikidata.py

 import json
 from requests import get
 from urllib import urlencode
+import locale
+import time
+import dateutil.parser
 
 result_count = 1
 wikidata_host = 'https://www.wikidata.org'
@@ -35,6 +38,16 @@ def response(resp):
     language = resp.search_params['language'].split('_')[0]
     if language == 'all':
         language = 'en'
+    
+    try:
+        locale.setlocale(locale.LC_ALL, str(resp.search_params['language']))
+    except:
+        try:
+            locale.setlocale(locale.LC_ALL, 'en_US')
+        except:
+            pass
+        pass
+    
     url = url_detail.format(query=urlencode({'ids': '|'.join(wikidata_ids),
                                             'languages': language + '|en'}))
 
@@ -164,10 +177,12 @@ def getDetail(jsonresponse, wikidata_id, language):
 
     date_of_birth = get_time(claims, 'P569', None)
     if date_of_birth is not None:
+        date_of_birth = dateutil.parser.parse(date_of_birth[8:]).strftime(locale.nl_langinfo(locale.D_FMT))
         attributes.append({'label': 'Date of birth', 'value': date_of_birth})
 
     date_of_death = get_time(claims, 'P570', None)
     if date_of_death is not None:
+        date_of_death = dateutil.parser.parse(date_of_death[8:]).strftime(locale.nl_langinfo(locale.D_FMT))
         attributes.append({'label': 'Date of death', 'value': date_of_death})
 
     if len(attributes) == 0 and len(urls) == 2 and len(description) == 0: