fix: support DNSLink with dnslink=/ipns/{libp2p-key} (#959)

* fix: change DNS resolution endpoint to allow ipns recursive resolution
* fix: make DNSLink check non-recursive

Given the current codebase, I believe we could make it a bit faster
by passing ?r=false (we only want to know if DNSLink is present,
don't need to resolve recursively, especially when users
start using /ipns/{libp2p-key} in DNSLink)

Co-authored-by: Jorge Pérez <jorge@ktlxv.com>
Co-authored-by: Marcin Rataj <lidel@lidel.org>

add-on/src/lib/dnslink.js

@@ -138,7 +138,7 @@ module.exports = function createDnslinkResolver (getState) {
       // js-ipfs-api does not provide method for fetching this
       // TODO: revisit after https://github.com/ipfs/js-ipfs-api/issues/501 is addressed
       // TODO: consider worst-case-scenario fallback to https://developers.google.com/speed/public-dns/docs/dns-over-https
-      const apiCall = `${apiProvider}api/v0/dns/${fqdn}?r=true`
+      const apiCall = `${apiProvider}api/v0/name/resolve/${fqdn}?r=false`
       const xhr = new XMLHttpRequest() // older XHR API us used because window.fetch appends Origin which causes error 403 in go-ipfs
       // synchronous mode with small timeout
       // (it is okay, because we do it only once, then it is cached and read via readAndCacheDnslink)