Yt library create swarm of yt-jobs with ssh connection similar to ml/nirvana/nope/examples/openmpi_runner

This libraries is usefull for collective computations like MPI, NCCL, etc

Usage
```
ya make .
# run job
./example_job --settings ./settings.yson  --ssh-key ../../../../qemu/guest_images/qavm/keys/id_rsa  --job-count 3

Linux vla2-8238-gpu-node-hahn.vla.yp-c.yandex.net 5.4.105-11 #1 SMP Mon Mar 15 08:58:33 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
Linux vla2-8238-gpu-node-hahn.vla.yp-c.yandex.net 5.4.105-11 #1 SMP Mon Mar 15 08:58:33 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
Linux vla2-8238-gpu-node-hahn.vla.yp-c.yandex.net 5.4.105-11 #1 SMP Mon Mar 15 08:58:33 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
Linux vla2-8238-gpu-node-hahn.vla.yp-c.yandex.net 5.4.105-11 #1 SMP Mon Mar 15 08:58:33 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
Linux vla2-8238-gpu-node-hahn.vla.yp-c.yandex.net 5.4.105-11 #1 SMP Mon Mar 15 08:58:33 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
Linux vla2-8238-gpu-node-hahn.vla.yp-c.yandex.net 5.4.105-11 #1 SMP Mon Mar 15 08:58:33 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
Result saved in //tmp/yt_ssh_swarm_exampleNiTzykEcpV/yt_ssh.out

```
