Build Variables Source Generator

[aritchie]

Resolves #2927

This is the initial implementation of proposed AOT build checks

Features

• Generates a precompiled list of msbuild properties we were interested in based on various issues within our repo
• Currently, we only look at PublishTrimmed and PublishAot in our AotHelper
• Generates module initializer only on runnable targets
• Ability to disable source generator if user encounters issue

TODO

• Unit Tests
• Document ability to disable source generator

[aritchie]

Before we release this, I would like to do a beta test to ensure all of the nuget stuff has zero issues. CC: @jamescrosswell

[bruno-garcia]

lots of stuff new to me so I don't have much to add, just a few suggestions