Unified project system (new TFM integration with build/publish/SWA)

[mkArtakMSFT]

• Support net8.0-browser TFM on the SDK and runtime side.
• Update Static Web Assets to account for multitargeted projects.
  • The project needs to include the assets produced by the net8.0-browser TFM.
  • We need to handle the different TFM combinations here
  • We need to do work to support multi-targeting during build and publish.

[javiercn]

#47885
dotnet/razor#8632
dotnet/runtime#85333