Align DB keys in legacy store for v3 blocks and transactions

[ishantiw]

Description

Align DB keys in legacy store for v3 blocks and transactions

In 5.3 version of SDK,

export const DB_KEY_BLOCKS_ID = 'blocks:id';
export const DB_KEY_BLOCKS_HEIGHT = 'blocks:height';
export const DB_KEY_TRANSACTIONS_BLOCK_ID = 'transactions:blockID';
export const DB_KEY_TRANSACTIONS_ID = 'transactions:id';

In legacy module,

export const DB_KEY_BLOCK_ID = Buffer.from([0]);
export const DB_KEY_BLOCK_HEIGHT = Buffer.from([1]);
export const DB_KEY_LEGACY_BRACKET = Buffer.from([2]);

Acceptance Criteria

• Should have all the DB keys aligned for the migration