system connections

[navidys]

new feature - system connection (ssh, unix and tcp)

• Similar steps as podman v4 system connections (add, remove, connect, disconnect, set default)
• Configurtion is saved under ~/.config/podman-tui/podman-tui.conf
• Before adding new SSH connection validation will be perform (similar to podman v4)
• Since podman bindings is using pkg/terminal which is writing to stdout and reading from stdin, therefore a bit complicated at the moment to read SSH identity phasephrase from UI, therefore phasepharase shall be set via "CONTAINER_PASSPHRASE" variable otherwise the application will set the OS environment "CONTAINER_PASSPHRASE=empty" and unset after application exits
• tests update to cover system connections commands
• docs update