getConfig cleanup of currency

[patmmccann]

Type of issue

getConfig is used by adapters to gather currency.adServerCurrency, currency, and floors.data.currency

Description

getConfig is a poor access point for bidders to a variety of fields, which may be dynamic to an ad unit and no longer match config.

Some examples:

Prebid.js/modules/adfBidAdapter.js

Line 63 in 56292c4

const currency = getConfig('currency.adServerCurrency');

Prebid.js/modules/beopBidAdapter.js

Line 140 in 56292c4

const publisherCurrency = config.getConfig('currency.adServerCurrency') || getValue(bid.params, 'currency') || 'EUR';

I propose these all get cleaned up to look at the request object field cur and that the object is autopopulated by config with the first element of the array being ad server currency