chore: remove hosts-file and zeustracker
[doh-server] update to 2.2.1
[dnscrypt-proxy] remove, replaced with plain dns query
[unbound] upstream to a plain dns
Increase dnscrypt-proxy max clients to 300
Switch to IPv4 internally

Trying to narrow down an issue where the server sometimes is really
slow to response.
Raise soacceptqueue and enable accf_http/accf_data for Nginx
Apply hardening playbook
Move SSH port to 4022
Use fifo to pass Ansible password instead of stdin
Massive cleanup and move to gridns.xyz.
Fix nginx configuration mis-redirecting letsencrypt requests.
Add Japanese-site specific blocklist.
Properly setup logger to discard request logs.

Due to misconfiguration, all requests prior to Sep 4, 2018 19:00 UTC
were logged by doh-proxy, which prints to STDOUT, and s6-svscan-log
capture those to /tmp/uncaught-logs.

In this commit I've proceed to properly configure s6 logger to discard
request logs from doh-proxy, as well as deleting all logs in the
server. I deeply apologize for not properly auditing this. :'(
Enable IPv6 and add cloudflare-ipv6 as DoH upstream.
Expose unbound directly in additional to DoH and some optimizations.
Force dnscrypt-proxy to use TCP and disable cache.

Another attempt at fixing SERVFAIL.