Make iostreams component work locally

[msimberg]

Either conditionally make it work with the local runtime, or add another implementation that always works locally.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[toktarev]

Is this issue still actual ?

[hkaiser]

Is this issue still actual ?

Yes! The question would be whether a simple mapping hpx::cout --> std::cout would already do the trick. I.e. something like a simple conditional

namespace hpx {
    using cout = std::cout;
}