repair: Add row level metrics
repair: Add row level metrics

Number of rows sent and received
- tx_row_nr
- rx_row_nr

Bytes of rows sent and received
- tx_row_bytes
- rx_row_bytes

Number of row hashes sent and received
- tx_hashes_nr
- rx_hashes_nr

Number of rows read from disk
- row_from_disk_nr

Bytes of rows read from disk
- row_from_disk_bytes

Message-Id: <35b9339f8cfc5b3e00f8ff30cd34c7157dfa9c0a@scylladb.com>

avikivity/scylla,scylladb/scylla,scylladb/scylla,avikivity/scylla,avikivity/scylla,scylladb/scylla,scylladb/scylla