Feature: Introduce new language features via `CompilerPlatform`

[Lamparter]

What feature or improvement do you think would benefit the app?

The Compiler Platform SDK currently contains packages that extend Roslyn. A nice addition to this would be packages that introduce helpful language features to simplify code and make using C# and other languages easier.

Version

No response

API Changes

This would require making a new section of projects and perhaps a Roslyn multitarget system for these language features.

Intended Use-Case

This would make the language simply easier to use.

Comments

This goes nicely alongside #1.