vpn_status: Add formatters for displaying IP addresses of VPNs

[jdholtz]

This commit adds the option to display IPv4 and IPv6 addresses of the VPNs in use (if using NetworkManager). I also added support for detecting OpenVPN VPNs because the connection type is tun (NetworkManager does not set the Vpn property to true for OpenVPN connections). I have found this change helpful to easily get my VPN IP when pen-testing.

There could be potential KeyError issues when attempting to retrieve the IP addresses, but I have not run into any problems with this.

In this change, I decided not to filter out when placeholders are None (likely for IPv6) and instead let the user decide to exclude them in the config (e.g. format = "{name} [\?if=ipv6 {ipv6}]").

[lasers]

In this change, I decided not to filter out when placeholders are None (likely for IPv6) and instead let the user decide to exclude them in the config (e.g. format = "{name} [?if=ipv6 {ipv6}]").

That's the way to go.

# shorter version
format = "{name} [{ipv6}]"

# ipv4 and/or ipv6
format = "{name}[ {ipv4}][ {ipv6}]"

# ipv4 and/or ipv6 using soft
format = "{name}[\?soft  ][{ipv4}][\?soft  ][{ipv6}]"

# etc

Not using py3status and from the looks of this history, @ultrabug can test this better than me.

My nitpicks are with existing i3status-related configs (such as pidfile, check_pid) possibly not part of loop now and if it makes sense to fix around some more to support both... such as pidfile now accepting a list of vpn pidfiles + check_pid = True to print VPN: yes, no instead of VPN: yes too.

And if this ought to still be a drop-in replacement? And maybe hardcoded color. Idk.

[jdholtz]

if it makes sense to fix around some more to support both

That does make sense. However, I think it would be best in a separate PR as adding support for multiple VPNs with check_pid doesn't connect with these changes.

[ultrabug]

Thanks a lot @jdholtz ; I don't use this module and can't test it so I trust your user input!