Add statistical I/O metrics

[kazmatsu256]

Outputs statistical I/O information contained in db.serverStatus().

• Additional metrics mongodb_wiredtiger_connection_read_IO_s mongodb_wiredtiger_connection_write_IO_s mongodb_wiredtiger_blockmanager_read_blocks_total mongodb_wiredtiger_blockmanager_read_bytes_total mongodb_wiredtiger_blockmanager_write_bytes_total mongodb_wiredtiger_blockmanager_write_blocks_total mongodb_wiredtiger_cache_read_time_usecs mongodb_wiredtiger_cache_write_time_usecs Mongodb_wiredtiger_cursor_calls {type = "create"} Mongodb_wiredtiger_cursor_calls {type = "Insert"} Mongodb_wiredtiger_cursor_calls {type = "Modify"} Mongodb_wiredtiger_cursor_calls {type = "Remove"} Mongodb_metrics_agg_stage_counter {type = "Lookup"}

• Test We are testing on the local machine using MongoDB (version: 4).