Implement ReplayAttack protection

[splix]

Implement ReplayAttack protection by introducing new signature component, based on BlockHash of last fork.

Key elements:

• optional, accept non-protected transactions on validation
• enable signing after block 3,000,000
  • accept new signature
  • sign with new component by default
• use hash of block 1,920,000
• write tests
• cli flag to disable new sign (optional task)
• cli flag to require new sign for mining (optional task)

Reference:

• https://github.com/ethereumproject/ECIPs/pull/10/files
• /core/types/transaction.go

[elaineo]

Are we decided on ECIP1011?

[splix]

@elaineo not decided yet, but we want to use this task as a test task for a new developer. We may accept it or not, but it's good enough to get familiar with the code.

[avtarsehra]

@splix, thanks this looks good.