make the useragent header fetch properly

add a salt to the generate_secret function -- that was kinda important right? lol
just pass through to `end` if not POST or GET
make it not use calls to hostname and dig in lua scripts, use haproxy backend resolving instead
improve the template a lot and make it theme-matched to my site and similar to ngx_http_js_challenge robot page
fix various bugs

src/libs/http.lua

@@ -609,7 +609,7 @@ function M.send(method, t)
     else
         return nil, "http." .. method:lower() .. ": Invalid URL schema " .. tostring(schema)
     end
-    print("ADDR IS", addr)
+
     local c, err = connect(socket, addr, port)
 
     if c then