Feature: ChainConfigurator, use interface for chain configuration

[meowsbits]

Migrated from: etclabscore/multi-geth-fork#68
Original author: @meowsbits

---

Interfaces are currently used for several important data types:

• ChainReader (implemented by core.HeaderChain and core.BlockChain)
• Engine
• core.BlockValidator, etc.

https://github.com/etclabscore/multi-geth/blob/master/consensus/consensus.go#L32

We should use an interface for chain configuration as well (eg type ChainConfigurator interface {...}. This is of particular importance for our growing chain config which has now far-overgrown the upstream implementation. The effort would be in order to establish common patterns of configuration implementation, to enable translation/conversion between configuration data types, and to further un-hardcode some of the configuration opinions.

Doing so would enable various Chain Configurations (ethereum/go-ethereum, parity, multi-geth, even Aleth, PyEthereum, Besu??...) to run "natively" w/o awkward adhoc conversion methods (https://github.com/etclabscore/multi-geth/blob/feat/x-chainspec-types-and-tests/params/convert/parity.go#L321, https://github.com/ethereum/go-ethereum/blob/master/cmd/puppeth/genesis.go#L366). It would also greatly simplify and validate some testing workarounds (https://github.com/etclabscore/multi-geth/blob/feat/x-chainspec-types-and-tests/tests/params.go#L136)

Essentially this helps us pay back some of the technical debt we've inherited from upstream opinions.

Rel #67

[meowsbits]

Resolved, now quite a while ago. See

core-geth/params/types/ctypes/configurator_iface.go

Line 40 in 1c53607

ChainConfigurator

.