move index creation for word table to tokenizer

This introduces a finalization routing for the tokenizer
where it can post-process the import if necessary.

nominatim/tokenizer/legacy_tokenizer.py

@@ -119,6 +119,15 @@ class LegacyTokenizer:
             self.normalization = properties.get_property(conn, DBCFG_NORMALIZATION)
 
 
+    def finalize_import(self, config):
+        """ Do any required postprocessing to make the tokenizer data ready
+            for use.
+        """
+        with connect(self.dsn) as conn:
+            sqlp = SQLPreprocessor(conn, config)
+            sqlp.run_sql_file(conn, 'tokenizer/legacy_tokenizer_indices.sql')
+
+
     def update_sql_functions(self, config):
         """ Reimport the SQL functions for this tokenizer.
         """