Visor runtime logs from `skywire-cli`

[0pcom]

The visor runtime logs are available from the hypervisor UI.

These same runtime logs can be viewed from the terminal with journalctl -u skywire but it's not possible to view the visor runtime logs from skywire-cli.

Only the app logs, to my knowledge, can be viewed from the cli with skywire-cli visor app log.

A subcommand skywire-cli visor log should be created for viewing the visor runtime logs.