[ACS-3194] API for linked rules

Do we definitely want to mention rulesets and rulesetIds? I don't think the client needs this, because it can always reference rulesets by a folder id. This will require a bit more work on the backend to be able to move rules around, but I think it's worth it to make the API more sane.

Example of backend needing to move rules around:

Create folder and rule: folder1 -> rules1
Create folder and link to rules: folder1 -> rules1 <- folder2
"Unlink" rules from first folder: rules1 <- folder2

Alfresco / rest-api-explorer

[ACS-3194] API for linked rules #159