refs https://github.com/TryGhost/Team/issues/3260
- We need a way to remove posts form collections without fetching the whole collection's content. This API method allows to remove posts from manual collections by collection id and post id.
- As a response it returns up to date collection state without the removed post.
closes https://github.com/TryGhost/Team/issues/3259
- API output mappers (soon to be serializers) are meant to work based on allowlist set of output properties. Having the allowlist early on will allow to track the API evolution consistently.
refs https://github.com/TryGhost/Team/issues/3294
- The factory method for the Collection and validations should live close together based on our latest architectural direction