Support parity

Outline

Currently the embark blockchain cmd as well as embark run launch a geth node by default. There is a -c option to specify the client, however only geth is currently supported. The goal of this task is to add support for parity such that embark blockchain -c parity will run a parity node with the options configured in config/blockchain.js and with the same functionality support as currently there is for geth.

Acceptance Criteria

• the following commands can launch a parity node: ** embark blockhain -c parity ** embark blockchain --client parity ** embark run --client parity
• The parity node will be run with the options configured in config/blockchain.js (example. all options should be supported.
• The same blockchain.js config file should work for both geth and parity. Although client specific parameters are acceptable. Common parameters like rpcHost should remain the same.
• If the isDev parameter is set to true then the parity node should be run using a developer friendly chain, equivalent to --dev option in geth, for e.g using PoA or something that will not trigger mining 100% of the time.

[Neurone]

@gitcoinbot Hi scary bot 😄 I completed the job five days ago, I’m waiting for PR approval.

[0x-r4bbit]

This had landed as https://github.com/embark-framework/embark/commit/bad9b97f1cc4a7792c2bf4fc9097ce5ac6ef26ea