Support installing correct package reference of ilcompiler for other OS's and arch's

[jsturtevant]

right now the project supports installing windows version of il compiler through out the project, for example:

componentize-dotnet/src/WasmComponent.Sdk/ImportInDev.proj

Line 10 in a66f726

<PackageReference Include="runtime.win-x64.Microsoft.DotNet.ILCompiler.LLVM" />

[jsturtevant]

fixed with #40