Fee recipients precompile

[ceyonur]

Adds fee recipients precompile to determine how rewards should be handled

1- Directly to a single address 2- Allowed Fee Recipients so minters can claim rewards for themselves 3- Disabled and fees directed to blackhole

• [x] Added precompile template and contract
• [ ] Verify blocks according to reward handler in state
• [ ] Build blocks according to reward handler in state (set coinbase correctly)
• [ ] Add contract call mechanism
• [ ] Tests