feat: allows disabling IPv4 or IPv6

[BPplays]

Closes #1039

Summary

allows disabling IPv4 or IPv6

known issues:

• disabling IPv4 causes DNS to stop working because there is no RDNSS support
• you can disable IPv6 and IPv4 at the same time, this is probably never wanted
• the button to disable IPv4 currently uses the localization label to disable IPv6
• there is no warning if the user is disabling the IP version they're currently using to connect

i've mostly been testing disabling IPv4 but testing disabling IPv6 does seem to work too

Checklist

• Ran make test_e2e locally and passed
• Linked to issue(s) above by issue number (e.g. Closes #<issue-number>)
• One problem per PR (no unrelated changes)
• Lints pass; CI green
• Tricky parts are commented in code

[86dd]

I think it would be important to add IPv6 RDNSS support before this is merged, as people will likely complain about broken DNS when disabling IPv4, and maybe add a warning or just refuse when the User disables both stacks, as this is well, an IP(v4/v6) KVM 😁