new word table layout for icu tokenizer

The table now directly reflects the different token types.
Extra information is saved in a json structure that may be
dynamically extended in the future without affecting the
table layout.

lib-sql/tokenizer/icu_tokenizer_tables.sql

@@ -0,0 +1,15 @@
+DROP TABLE IF EXISTS word;
+CREATE TABLE word_icu (
+  word_id INTEGER,
+  word_token text NOT NULL,
+  type text NOT NULL,
+  info jsonb
+) {{db.tablespace.search_data}};
+
+CREATE INDEX idx_word_word_token ON word
+    USING BTREE (word_token) {{db.tablespace.search_index}};
+GRANT SELECT ON word TO "{{config.DATABASE_WEBUSER}}";
+
+DROP SEQUENCE IF EXISTS seq_word;
+CREATE SEQUENCE seq_word start 1;
+GRANT SELECT ON seq_word to "{{config.DATABASE_WEBUSER}}";

nominatim/tokenizer/legacy_icu_tokenizer.py

@@ -152,7 +152,7 @@ class LegacyICUTokenizer:
         """
         with connect(self.dsn) as conn:
             sqlp = SQLPreprocessor(conn, config)
-            sqlp.run_sql_file(conn, 'tokenizer/legacy_tokenizer_tables.sql')
+            sqlp.run_sql_file(conn, 'tokenizer/icu_tokenizer_tables.sql')
             conn.commit()
 
             LOG.warning("Precomputing word tokens")