Allow naming of executables

[IwanKaramazow]

the following entry

{
    "backend": "native",
    "main-module": "Utf8_test"
}

results in a utf8_test.native executable.

When building an executable for a windows system, it would be convenient if we could give the executable another name & extension.
Example: utf8_test.native would become runtest.exe

[bsansouci]

Ok I can add a field “name”.
What’s your current usecase

[IwanKaramazow]

I've got two use cases:

1. Windows: there's a restriction which requires executables to be named as .exe.
2. (More of a question) If I'm developing a medical app called "doctor", and the main entry-point is a module called Startup. Am I forced to rename the Startup-module to Doctor to have a nice name on the executable? Post-hoc renaming with a shell script doesn't feel like the best workflow in the world.