Core: coordinator interfaces and models

[nkostoulas]

Design and implementation of all crucial interfaces for the coordinator daemon:

• main coordinator

• config

• challenger

• service chain mock

• service chain

• client chain mock

• client chain

• storage mock

• storage

• listener mock

• listener

• verifier

• generate response stats

Models:

• Request

• Bid

• Challenge State

• Challenge Response

• Challenge Results

• Listener Messages