add module initializer #219

implement module initializers by annotating like in c#

using System.Runtime.CompilerServices;
class C
{
    [ModuleInitializer]
    internal static void M1()
    {
        System.Console.WriteLine("init1");
    }

    [ModuleInitializer]
    internal static void M2()
    {
        System.Console.WriteLine("init2");
    }

    static void Main() {
        System.Console.WriteLine("main");
    }
}

the compiler will collect all annotated method and call them in

internal class <Module>
{
    static <Module>()
    {
        C.M1();
        C.M2();
    }
}

this should be only allowed in applications not in libraries, see https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca2255