clean_housenumbers: make kinds and delimiters configurable

Also adds unit tests for various options.

nominatim/tokenizer/sanitizers/split_name_list.py

@@ -9,21 +9,16 @@ Sanitizer that splits lists of names into their components.
 
 Arguments:
     delimiters: Define the set of characters to be used for
-                splitting the list. (default: `,;`)
+                splitting the list. (default: ',;')
 """
-import re
-
 from nominatim.errors import UsageError
+from nominatim.tokenizer.sanitizers.helpers import create_split_regex
 
 def create(func):
     """ Create a name processing function that splits name values with
         multiple values into their components.
     """
-    delimiter_set = set(func.get('delimiters', ',;'))
-    if not delimiter_set:
-        raise UsageError("Set of delimiters in split-name-list sanitizer is empty.")
-
-    regexp = re.compile('\\s*[{}]\\s*'.format(''.join('\\' + d for d in delimiter_set)))
+    regexp = create_split_regex(func)
 
     def _process(obj):
         if not obj.names: