ETC Config change backport (#4056)

* delay bomb for Classic (ECIP-1010) (#3179)

* delay bomb for classic (ECIP-1010)

* formatting fix after core review, rel [e6b50936]

* Replay protection for Classic

* EIP-155 configuration for Ethereum Classic

* EIP-160 configuration for Ethereum Classic

* Testnet for Ethereum Classic

* revert ETC to correct Network ID

* reuse Morden for Classic Testnet

* set CHAIN_ID for Classic (#3934)

* configurable CHAIN_ID

* set CHAIN_ID for Ethereum Classic

* prettify classic json