[IMPROVE] Add functionality to handle multiple Coinbase Pro portfolios

[marcelonyc]

What's the feature that should be improved? Currently, OpenBBTerminal allows a single Coinbase portfolio definition (One API key per portfolio). Multiple portfolios can be configured in Coinbase Pro. Functions dealing with accounts and orders need to be able to select the portfolio to work on.

Describe how you would like the feature improved For this, to work we need to allow multiple keys for Coinbase Pro. See https://github.com/OpenBB-finance/OpenBBTerminal/issues/1699 After multiple key management is implemented, each of the broker functions needs to implement a portfolio selection option or parameter as well as a consolidated view of all portfolios.

As an alternative, I can build the portfolio key management into the bro/cb functions. I am waiting for feedback before I start any development on this feature.

Possibly describe the ideal way to improve this I have a to think about this :) So far I have questions... How does a trader look at multiple portfolios in one broker? What is the value of consolidating the view from multiple portfolios? As the functionality improves, how does having multiple portfolios affect the view of the account and position?