unbound/blocklist: uncomment vector.im, add use-application-dns.net

* Vector.im is the identity server that gets restored by itself and I
  don't seem to ever have any business to Vector.im website, while
  the other domains I need to visit at times.
* use-application-dns.net being NXDOMAIN tells Firefox to not send
  traffic to Cloudflare DoH. I thought of this when I saw the news and
  got courage to actually do this after seeing that DNSCrypt-proxy also
  does so.

etc/unbound/unbound.conf.d/blocklist.conf

@@ -4,7 +4,14 @@
 # a bit controversial, so I am keeping them commented in git.
 #local-zone: "matrix.org" static
 #local-zone: "modular.im" static
-#local-zone: "vector.im" static
+# I have seldom need to access vector.im, while the above, especially
+# matrix.org I actally need at times for documentation.
+local-zone: "vector.im" static
 
 # THROWAWAY
 local-zone: "publicbt.com" static
+
+# Tell Firefox to not automagically send traffic to Cloudflare as there is
+# this Unbound using DNS-over-TLS / DNSCrypt without the need for it to use
+# separate DNS.
+local-zone: "use-application-dns.net" static