The SDK should provide a RID-negotiation Task for other tools to use

[baronfel]

Is your feature request related to a problem? Please describe.

There are now two examples of partner teams needing to perform RID-negotiation as part of their normal order of business

• containers use RID-negotiation to map from multi-arch container synthetic RIDs to find the best match for the .NET RID being targeted
• Aspire uses RID-negotiation to influence which implicit PackageReferences to add on Restore

Describe the solution you'd like

In both cases the core logic is very simple:

• using a given RID graph path
• and a set of 'supported RIDs'
• and a single 'target RID'
• return the 'supported RID' that is the 'best fit' for the 'target RID'

If we shipped this in-box we'd simplify the needs of partner teams and provide a way to surface more 'hidden' data that the SDK already knows about.