add streaming

[kamilsk]

retry --stream-to=12345 -- do command

retry starts listen 12345 TCP port to stream stdout/stderr of executed command to it.

can be useful https://blog.kowalczyk.info/article/wOYk/advanced-command-execution-in-go-with-osexec.html

some inspiration:

• https://github.com/wagoodman/bashful