Enhance: Add Merkle Root On Main Block (for transactions)

[sukrawidhyawan]

Description

This Implementation will build the Merkle Root & Merkle Tree main block. The leaf of Merkle Root comes from the transactions included in the block. Field Merkle Root & Merkle Tree already added into the Block model when adding Merkle Root for spine block (related issue: #1205 ), it makes can directly into step on building Merkle Root on the main block

Breakdown

• Build Merkle root for the main block from its transaction if exist otherwise leave it nil
• Enhance validation main block to validate the Merkle Root when receiving a complete block (already included the transactions).
  • One of the options is selecting the random transaction of the block, build the intermediate hashes from Merkle Tree & validate the Merkle Root

Expected behavior

blocks will have Merkle Root & Merkle Tree & can validate it's Merkle when receiving from other peers