refs https://github.com/TryGhost/Team/issues/2204
This was found during Tiers flows testing, the logic for fetching
price information from Tiers had not been updated to use the new Tiers
package and Payments service. This only affects Tiers created since 5.22.x
refs https://github.com/TryGhost/Team/issues/637
All the APIs that currently work with price names needs to be updated to work with price ids instead to work with custom prices/products. This change updates APIs to work with Price IDs in `checkout` , `updateSubscription` and other APIs/methods.
refs https://github.com/TryGhost/Team/issues/530
The RouterController was a grab bag of all controller methods, making it
difficult to mock & test. This adds a MemberController with a smaller
API - making it easier to test.
