SBOM generation support for .NET Applications

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

.NET Developers should be able to have an integrated, robust SBOM generation capability in the toolchain, so that .NET applications and libraries have correct, updated SBOMs for consumers of the software to use.

### Describe the solution you'd like

This epic tracks the work list to complete integration of Microsoft.SBOM.Targets into the .NET SDK. In the simplest case, as soon as a user sets `true`, the SDK should

* insert an implicit PackageReference to [Microsoft.SBOM.Targets](https://www.nuget.org/packages/Microsoft.Sbom.Targets)
* ensure that the SBOM generation provided by that package is hooked into the `publish` target
* ensure that relevant .NET toolchain information is provided to the SBOM generation to ensure that future analysis has good traceability of the artifacts