Flesh out the GetProjectReferenceMetadata task

[dougbu]

Is this a Bug or Feature request?

Enhancement that's part of #4896

Description of the problem

The current GetProjectReferenceMetadata task is basically a stub. It needs to get the requisite metadata and add it to the Inputs items i.e. behave like GetFileReferenceMetadata and GetUriReferenceMetadata but with ServiceProjectReference items. See expected metadata in the <ItemDefinitionGroup/> at https://github.com/aspnet/Mvc/blob/364b3a7720cb6f925b0eea39ef8e7e8df47af57d/src/Microsoft.Extensions.ApiDescription.Client/build/Microsoft.Extensions.ApiDescription.Client.props#L59-L104

Of course, also need to use this task in Microsoft.Extensions.ApiDescription.Client.targets and thereby simplify the ServiceProjectReferenceGenerator target.

This issue will not remove the need for the GetDocumentInsider to retrieve information from the web site project prior to doing its work. Most metadata the inside man needs e.g. a default %(Uri) is not generic enough to be of interest in other document generators.

Version of Microsoft.AspNetCore.Mvc or Microsoft.AspNetCore.App or Microsoft.AspNetCore.All

See the features/client.code.generation branch branch. That work is intended for the 2.2 Preview 3 milestone.

[dougbu]

Oops, realized this will complete when my draft PR for #8242 (expected tonight or tomorrow). Moving to same milestone as that issue. I continue to work on both issues.

[dougbu]

Removed this task entirely when creating the Microsoft.Extensions.ApiDescription.Server package (b3ddd65) and rewriting the GetDocumentInsider tool (4c8ca0b). Cleanup is done.