Additional validation for IO roots

[kostko]

After #2053 the runtime storage nodes should perform additional validation when accepting updates via Apply for IO roots:

• The format of each key must be a valid transaction key or a valid tag key.
• The number of transaction inputs or outputs must be at most runtime.txn_scheduler.max_batch_size.
• The size of transaction inputs must be at most runtime.txn_scheduler.max_batch_size_bytes.