Optional Arguments for useful postgres settings during create_index #16

It could be useful to optionally allow users to provide a statement_timeout during create_index as it can be difficult to interrupt once started and could potentially take a long time if the table contains a lot of data

For IVFFLat indexes, insufficient maintenance_work_mem can cause the index creation to fail at the last step. ref. This should be an optional argument to create_index to make it possible to adjust when the postgres role has sufficient permission