Document the precedence / behavior in case of multiple package configuration providers

[sschuberth]

This

https://github.com/oss-review-toolkit/ort/blob/811daef3d35abb440a1ad044bcbf14738fc95767/model/src/main/resources/reference.yml#L42-L51

should be documented similar to curation providers at

https://github.com/oss-review-toolkit/ort/blob/811daef3d35abb440a1ad044bcbf14738fc95767/model/src/main/resources/reference.yml#L53-L55

[sschuberth]

It probably makes sense to implement https://github.com/oss-review-toolkit/ort/issues/6972 first.

[mnonnenmacher]

It probably makes sense to implement #6972 first.

Multiple package configurations from different sources should already be allowed since #5334.

[sschuberth]

Multiple package configurations from different sources should already be allowed since #5334.

Right, but not if they apply to the same ID / provenance. The mentioned check is still there.

[mnonnenmacher]

Multiple package configurations from different sources should already be allowed since #5334.

Right, but not if they apply to the same ID / provenance. The mentioned check is still there.

That check is only internal in the SimplePackageConfigurationProvider and not applied to package configurations from different providers, so it's not really related to this issue which is about the behavior with multiple providers. See the commit message of https://github.com/oss-review-toolkit/ort/pull/5334/commits/1f9779817539d341e7d734e40baa09d0418a0d73.