Also removed the dependency on Microsoft.Extensions.CommandLineUtils.Sources NuGet package and instead just checking the source files into our repo as internal classes.
Fix#2526
- Added --version-suffix to build and publish
- Support reading DOTNET_* version variables everywhere versions can be read
- Show the commit sha in dotnet --version
- Added tests that check the assembly output version
- Set DOTNET_BUILD_VERSION when producing the CLI app itself so that it has the version information stamped in for help.
