Catalogs documentation issues

A few minor issues in the catalogs documentation:

1. The documentation mentions the access method is 'catalog/db', where in reality it is 'catalog.db'.
2. The 'mariadb-install-db' documentation says the catalog options are in 11.3
3. There is mention of `use-catalogs`, for MariaDB Server, but the option is `catalogs`. I think it is also implicit anyway (I haven't fully tested this).