feature: TOASTER_WEBMAIL_PROXY=nginx

[msimerson]

• feat: as an alternative to haproxy, use the installed nginx as the reverse proxy
  • nginx: support TOASTER_WEBMAIL_PROXY=nginx
  • webmail: add https proxy config, for TOASTER_WEBMAIL_PROXY=nginx
  • previously, haproxy sent proxy_protocol v2. Eventually, everything should use Forwarded (RFC 7239), for now we use the lowest common denominator: X-Forwarded-For
• fix: newsyslog.conf.d files must end with .conf
• fix(mail_dmarc): install .ini file in correct location
• data: standardize dirs in /data
  • mt: stage_setup_tls populates /data/etc/tls
  • dovecot: /data/etc/ssl -> /data/etc/tls
  • haproxy: /data/ssl.d -> /data/etc/tls.d
  • webmail: acme document root /data -> /data/htdocs
• letsencrypt: install acme.sh from ports
• letsencrypt: updates for etc/tls, add webmail deploy script
• mua: for testing, find or install curl, fixes dovecot.sh still fails error: provision/dovecot.sh: curl: not found #594
• mysql: use jail_is_running (noop)
• roundcube: configure SA user prefs plugin
• mt: added stage_enable_newsyslog, used in nginx, php, haraka, mongodb, redis, rspamd, spamassassin
• geoip: switch updater to geoipupdate, fixes geoip.sh fails using maxmind-geolite-mirror while downloading DB's #591

Checklist:

• docs up-to-date