Strict checking on transactions

[kroggen]

Proposal: implement a more strict checking on transactions according to the transaction type:

TRANSFER

The recipient must be filled
The amount must be non-zero
The payload must be zero bytes

CALL and FEEDELEGATION

The recipient must be an existing smart contract
The payload must be valid, a proper formatted JSON for a call

GOVERNANCE

The payload must be valid, a proper formatted JSON for a governance call
The recipient must be either aergo.system (DPoS) or aergo.enterprise (Raft)

DEPLOY

The recipient must be empty
The payload must be a valid smart contract binary code

REDEPLOY

The recipient must be a valid smart contract
The payload must be a valid smart contract binary code

PAYLOAD (new type)

The payload must be non-zero bytes
The amount must be zero
The recipient can be empty or filled

NORMAL

Currently supports any recipient, any amount and any payload
This transaction type could be deprecated
It could be supported for backwards compatibility for some time, and encourage users to migrate to other types

[kroggen]

These issues are related:

#141
#143
#144
#145