Integrate SBOM generation into application publishing

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

The .NET SDK should generate SBOMs for published applications. As part of publishing, we should trigger SBOM generation from Microsoft.SBOM.Targets. The SBOMs should contain information about the NuGet packages consumed by the application, as well as relevant data about the SDK, Workloads, and Toolchain used to build the application.

Today, the NuGet package detection is handled well, but the build-time information is not currently represented in microsoft/sbom-tool. We may need additional integration points to provide that information to the tool.

### Additional context

A quick version of what this integration might look like is available at https://github.com/baronfel/dotnet-app-sbom-sample.