refs https://github.com/TryGhost/Product/issues/4153
- We need use the `created_at` timestamp in the new AdminX offers. The
API doesn't return that value.
- With this change the API returns the created_at property so that we
can consume it.
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This pull request adds a `createdAt` property to the offer domain model,
data transfer object, and repository. This allows tracking and auditing
the creation and modification of offers and offer codes in
`ghost/offers`.
refs https://github.com/TryGhost/Team/issues/2400
- we've deemed it useful to start to return `Content-Version` for all
API requests, because it becomes useful to know which version of Ghost
a response has come from in logs
- this should also help us detect Admin<->Ghost API mismatches, which
was the cause of a bug recently (ref'd issue)
refs https://github.com/TryGhost/Team/issues/1726
- free trial offers don't need a stripe coupon created for them
- checkout sessions for free trial offers ignore stripe coupon and directly pass the trial days value
- trial days of an offer take precedence over trial days added as default to a tier
refs https://github.com/TryGhost/Toolbox/issues/354
- this commit turns the Ghost repo into a monorepo so we can bring our
internal packages back in, which makes life easier when working on
Ghost
