A recent combination of Coinbase and ccxt changes will now result in
authentication errors (server error 401) because of docker-finance's
coinbase implementation (specifically, direct calls to internal ccxt).
docker-finance's previous usage of request() meant hooking into the
underlying ccxt API and not the end-user public-facing API (publicly
documented - not necessarily the "public" vs "private" APIs provided by
exchanges, as seen in ccxt documentation).
This direct usage of request() was obviously never recommended but it
was always easier to interact with to get to the underlying raw object
(at least at the time of original docker-finance coinbase writing).
Since it appears that ccxt has refactored the authentication mechanism
related to request(), this commit also refactors in order to provide a
working fix for authentication.