add/improve reverse-proxy examples

* add haproxy, lighttpd, traefik, caddy

* adjust nginx buffer sizes for way faster downloads

* move unix-socket to /dev/shm/ because
   fedora sets PrivateTmp=true for nginx (orz)

contrib/haproxy/copyparty.conf

@@ -0,0 +1,24 @@
+# this config is essentially two separate examples;
+#
+#   foo1 connects to copyparty using tcp, and
+#   foo2 uses unix-sockets for 27% higher performance
+#
+# to use foo2 you must run copyparty with one of the following:
+#
+#   -i unix:777:/dev/shm/party.sock
+#   -i unix:777:/dev/shm/party.sock,127.0.0.1
+
+defaults
+  mode http
+  option forwardfor
+  timeout connect 1s
+  timeout client 610s
+  timeout server 610s
+
+listen foo1
+  bind *:8081
+  server srv1 127.0.0.1:3923 maxconn 512
+
+listen foo2
+  bind *:8082
+  server srv1 /dev/shm/party.sock maxconn 512