Like we do in the [Projects API](https://docs.gitlab.com/ee/api/projects.html#edit-project), we need to allow moving the snippet shard from one node to another. For this, we need to add new `repository_storage` param (available only for admins) in both project and personal snippets update REST endpoints. We need to update also the `Snippets::UpdateService` to implement this action. In general, there is a lot of logic that can be shared by both projects and snippets. It's worth to take a closer look and design a strategy that can avoid duplicating code and functionality.