move word table and normalisation SQL into tokenizer

Creating and populating the word table is now the responsibility
of the tokenizer.

The get_maxwordfreq() function has been replaced with a
simple template parameter to the SQL during function installation.
The number is taken from the parameter list in the database to
ensure that it is not changed after installation.

lib-sql/tokenizer/legacy_tokenizer_tables.sql

@@ -0,0 +1,19 @@
+DROP TABLE IF EXISTS word;
+CREATE TABLE word (
+  word_id INTEGER,
+  word_token text NOT NULL,
+  word text,
+  class text,
+  type text,
+  country_code varchar(2),
+  search_name_count INTEGER,
+  operator TEXT
+) {{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}}";