Add option to navigate proper dlls with IL Viewer

[kamyker]

Currently IL Viewer inspects dlls builds manually in Rider but they don't have code generated for ex. by Mono.Cecil.

If it can't be default then there should be an option to point csproj OutputPath to Library\ScriptAssemblies as was reverted in this commit f5a6fea .

Changed OutputPath to Library\ScriptAssemblies locally in your package and everything seems fine. Why it can't be like that by default? Build button should also be disabled in that case as it's pointless in Unity that doesn't use MSBuild but their own solution.