The existing INFORMATION_SCHEMA.TABLE_PRIVILEGES displays only those
privileges that were specifically granted on the table level,
whereas it may be useful to see privileges granted at the database
and global level.

This commit adds a new view `table_privileges` to the `sys` schema
for that purpose. The view shows privileges on existing tables
and views, combining all possible levels:
 - user_privileges
 - schema_privileges
 - table_privileges