Document the criteria for DNS servers (#1111)

* dns_provider initial commit

* continue DNS provider criteria

* .github/7_DNS_provider: require DNSSEC

* simplify wording

* finish

* turn required features a checkbox

* say Android 9+ instead of Android (<9)

* implement nitrohorse's suggestion

.github/ISSUE_TEMPLATE/7_DNS_provider.md

@@ -0,0 +1,36 @@
+---
+name: "🗄️ encrypted DNS provider suggestion"
+about: Suggest a new encrypted DNS provider.
+title: "🗄️ DNS provider suggestion | "
+labels: 🌐 website issue, 🗄️ DNS
+---
+
+<!-- Please feel free to overwrite these comments -->
+
+## Basic Information
+
+**Name:** 
+**Filtering:** <!-- What is being filtered? Is it opt-in with separate address or not? -->
+**Privacy policy:** <!-- Link, especially when there is logging -->
+**Protocols:** <!-- at least DoH or DoT? DNSCrypt? -->
+**Server/Location:** <!-- Where is the provider based? Where are their servers located? Anycast if there are multiple servers answering to the same address -->
+**Source:** <!-- link to the source code, preferred, but optional -->
+**Type:** <!-- Non-profit, commercial, hobby project? -->
+**Website:** 
+
+## Description
+
+<!-- Why should we list your suggestion? Anything else, that you wish us to know? -->
+
+
+### Required features:
+
+<!-- DoH and DoT are supported natively by platforms like Firefox and Android 9+ -->
+
+* [ ] supports DoH or DoT <!-- We love DNSCrypt, but there is already https://github.com/DNSCrypt/dnscrypt-resolvers which is directly supported by dnscrypt-proxy, so we don't consider useful to list providers only supporting it.  -->
+* [ ] supports DNSSEC <!--  https://dnssec.vs.uni-due.de/ can test your current DNS provider. -->
+* [ ] doesn't log IP addresses during normal operation <!-- If your suggestion logs, please compare its privacy policy with other servers on our table that keep logs. -->
+
+#### Desired features
+
+* [ ] supports QNAME minimization <!-- if you have access to the dig command, `dig +short txt qnamemintest.internet.nl` -->