Customer and WCAnalyticsCustomer: Disambiguate `userID` and `customerID`#16056

staskus wants to merge 12 commits intotrunkwoocommerce/woocommerce-ios:trunkfrom

woomob-1045-user-id-and-customer-id-for-both-wc-analytics-customer-and-customerwoocommerce/woocommerce-ios:woomob-1045-user-id-and-customer-id-for-both-wc-analytics-customer-and-customerCopy head branch name to clipboard