feature: simple support DOH server

etc/smartdns/smartdns.conf

@@ -30,6 +30,8 @@
 #      tls cert file
 #   bind-cert-key-pass [password]
 #      tls private key password
+# bind-https server
+#   bind-https [IP]:[port][@device] [-group [group]] [-no-rule-addr] [-no-rule-nameserver] [-no-rule-ipset] [-no-speed-check] [-no-cache] [-no-rule-soa] [-no-dualstack-selection]
 # option:
 #   -group: set domain request to use the appropriate server group.
 #   -no-rule-addr: skip address rule.