Move interrupt to separate package

[newhoggy]

polysemy-conc does not compile on windows because of the dependency on unix.

Only interrupt modules in the package actually require unix. polysemy-conc can easily be made to compile on Windows if the interrupt modules are moved to a separate package.

[tek]

yeah I guess that's a reasonable solution. but the obvious candidate for this effect is polysemy-process, since that already depends on unix 🙂

I moved it there in main, gonna publish to Hackage later.