Expand list of sample/starter DNS server entries

[atc0005]

Overview

These are already part of our list and I believe this project is fully compliant with their inclusion:

Server IP	Description
1.1.1.1	CloudFlare
8.8.4.4	Google
8.8.8.8	Google
208.67.222.222	OpenDNS

I don't know the terms of use, but these servers were listed as options for the https://digwebinterface.com web tool:

Server IP	Description
8.8.4.4	Google
165.87.13.129	AT&T (US)
1.1.1.1	CloudFlare
8.26.56.26	Comodo (US)
8.8.8.8	Google
168.95.1.1	HiNet (TW)
208.67.222.222	OpenDNS
9.9.9.9	Quad9
144.217.51.168	Securolytics (CA)
195.129.12.122	UUNET (CH)
192.76.144.66	UUNET (DE)
158.43.240.3	UUNET (UK)
198.6.100.25	UUNET (US)
64.6.64.6	Verisign (US)
77.88.8.8	Yandex (RU)

Review list

• https://www.lifewire.com/free-and-public-dns-servers-2626062
• https://digwebinterface.com
• https://dnschecker.org/dns-servers.php
• https://adguard.com/en/adguard-dns/overview.html
• https://github.com/AdguardTeam/AdGuardHome
• https://www.quad9.net/
• https://github.com/janmasarik/resolvers/blob/master/resolvers.txt

[atc0005]

See also #21.

[atc0005]

Another resource:

https://dnschecker.org/dns-servers.php

Looks like they have a pretty comprehensive list of available DNS servers. It's probably going to be worth keeping the provided list in this repo reasonably small and just link to reputable DNS-related sites that already provide/maintain current DNS server lists.

[atc0005]

• https://adguard.com/en/adguard-dns/overview.html
  • https://github.com/AdguardTeam/AdGuardHome

Could be interesting to compare against other servers in a list.