BE dashboard displays invalid data for Avg Trxs/block field

1. enable live syncing
2. Observe Avg Trxs/block value
3. Value changes block by block -> probably field is improperly described or returned data are invalid (and point number of transactions from last block not average).

Also if we want to see average value, the field label should contain information specific to number of blocks included in calculation.

Similar information should be specified for Max transaction count.

Maybe whole section should be properly described.