add dmsgpty-cli to skywire-cli

[mrpalide]

Did you run make format && make check? Yes

Fixes #863

Changes:

• add dmsgpty command groups to skywire-cli as follow:
  • skywire-cli dmsgpty list to get list of all remote visor connected to hypervisor
  • skywire-cli dmsgpty start <pk> to start dmsgpty command line interface. Just note that if remote visor connection lost, then its appear on skywire-cli dmsgpyt list command yet, but when trying to start dmsgpty, get error after a while (about 10 second).

How to test this PR:

• run a hypervisor
• run a visor and set hypervisor PK to its config
• use skywire-cli dmsgpty list check that visor connected and available
• use skywire-cli dmsgpty start <pk> to run dmsgpty command line interface of remote visor in your terminal

ScreenCast:

dmsgpty.mp4

[ersonp]

Getting this when trying to connect to the visor on arch-dev

erson@erson-69:~/Workspace/Go/skywire$ ./skywire-cli dmsgpty start 03efcc15721fda2f9b24e128d86154fb8a1043eb09ee747b60b9b9533b8d1b7cc3
[2022-06-09T12:34:04+05:30] INFO [dmsgpty-cli]: Requesting... address="unix:///tmp/dmsgpty.sock"
2022/06/09 12:34:04 Failed to execute command: failed to connect to dmsgpty-host: dial unix /tmp/dmsgpty.sock: connect: permission denied

[mrpalide]

Getting this when trying to connect to the visor on arch-dev

erson@erson-69:~/Workspace/Go/skywire$ ./skywire-cli dmsgpty start 03efcc15721fda2f9b24e128d86154fb8a1043eb09ee747b60b9b9533b8d1b7cc3
[2022-06-09T12:34:04+05:30] INFO [dmsgpty-cli]: Requesting... address="unix:///tmp/dmsgpty.sock"
2022/06/09 12:34:04 Failed to execute command: failed to connect to dmsgpty-host: dial unix /tmp/dmsgpty.sock: connect: permission denied

When you run your hypervisor skywire-visor by root permission (with sudo command), then should run skywire-cli with sudo too.

[0pcom]

Flawless!

[0pcom]

I am surprised that you couldn't import the dmsgpty-client command directly from the other repo; but it may be better to do it this way.

It works great, and it's impressive that it did not actually take you very long at all to make it work.

I've been waiting a long time for this exact functionality, thanks very much for your work here.