Poloniex client side authentication flow

[einsteinx2]

I'm not familiar with the API to I'll leave the details to @wolffan. This issue is to track whatever is needed to complete an authentication on the client side. An authenticate function in the PoloniexApi struct, plus whatever else is needed.

[einsteinx2]

Part of the authentication should probably create the institution object so that accounts can be related to it. With Plaid, we created institutions after signing in to a bank, but in this case, each authentication to Poloniex is another institution as a user could have multiple accounts, and Poloniex only has it's own accounts so there will only ever be one institution per authentication.

[wolffan]

For info: poloniex API is autenticated on every request with an API key and a secret per user.
So all transactions will use this as base authentication.

[wolffan]

This is already done on poloniex-xc9 #60

[wolffan]

Poloniex doesn't have an "account" per se, we just hit the endpoint with specific parameters, unsure if the institution applies and how to use it...
CORRECTION: used to store credentials

[einsteinx2]

Done