Connector status indicator

[fengtality]

Why

Since Hummingbot is letting external developers build and maintain certain exchange connectors, we need a system to ensure that users know which connectors are working properly and which ones aren't.

What

• Add a field called status to each connector
• Status can either be red / yellow / green
• red means that a connector doesn't work, yellow means that the connector works but has issues, while green means a connector is working properly
• starting with the v0.33 release, our team will mark status of each connector right before release date

How to communicate to users

• Add a column to https://github.com/coinalpha/hummingbot README.me for status
• Add a column to connect command for status
• If one of the exchanges in a strategy config file is a red or yellow connector, display a warning message when the user runs start