Cozy logger

Logger used by connectors.

It should only be used for connectors and services. For webapps, prefer cozy-minilog for the following reasons:

• Better readability
• Logs can be catched correctly in Sentry

Depending on NODE_ENV, it will either :

• log with colors in a human friendly way switch (NODE_ENV == "developement" || "standalone" || "test")
• log in JSON for logs to be picked up by the stack (NODE_ENV == "production")