Support Package Source Mapping in the Package Manager UI

[nkolev92]

issue captures all the additions for Package Source Mapping in the Package Manager UI.

Note that this does not include the NuGet Options UI, that's a different task, #11361

This issue captures creating clarity and ensuring the spec is up to date with whatever gets implemented.

Refer to the design here: https://github.com/NuGet/Home/blob/dev/implemented/2021/PackageSourceMapping.md
Design issue: #10730

Some questions that may need clarity.

• How does browse account for PackageSourceMapping?
• How do Update/Installed tabs account for PackageSourceMapping

Prerequisite:

• Design Package Source mapping package installation experiences in VS PM UI #11378

17.7

• https://github.com/NuGet/Client.Engineering/pull/2016
• Update Package Source Mapping in VS / PM UI Spec #12303
• Package Source Mapping UI - PM UI Actions support source pinning & create mappings in nuget.config #11797

17.8

• https://github.com/NuGet/Client.Engineering/issues/2123
• Create Package Source Mappings during Installation/update through PM UI  #11366
• Telemetry to Count Top Level & Transitive source mappings automatically created NuGet.Client#5377
• (Cancelled) Consider revising status to "Requires a source mapping or select a single source" #12830

17.9

• https://github.com/NuGet/Client.Engineering/issues/2421
• Create NU Error Code for Package Source Mapping & GPF conflicts #12953

Future (loosely priority order)

• Enable Automatic Package Source Mapping for Packages.config style projects #12832
• Consider a docs link in the Details Pane to explain Package Source Mapping #12829
• https://github.com/NuGet/Client.Engineering/issues/2554
• Spec: Integrate the onboarding features of PackageSourceMapper into VS #12834
• Consider Package Source Mapping sources for services in NuGet.PackageManagement.VisualStudio #12783
• Cleanup GPF while using a PackageSourceMapping when a failed Restore brought in the package  #12850
• https://github.com/nuget/client.engineering/issues/1406
• Support multi-select sources in PM UI's Package Source dropdown #12831
• https://github.com/NuGet/Client.Engineering/issues/2444
• https://github.com/nuget/client.engineering/issues/1393
• https://github.com/nuget/client.engineering/issues/1386
• When renaming a Package Source, any existing Source Mappings need to be updated #12936