add disable stdout option

[dogancanbakir]

Closes #1692

package main

import (
	"fmt"
	"log"

	"github.com/projectdiscovery/goflags"
	"github.com/projectdiscovery/httpx/runner"
)

func main() {
	results := map[string]struct{}{}

	options := runner.Options{
		Methods:         "GET",
		Timeout:         5,
		Threads:         80,
		Silent:          true,
		RandomAgent:     true,
		Retries:         2,
		DisableStdout:   true,
		InputTargetHost: goflags.StringSlice{"scanme.sh", "projectdiscovery.io", "localhost", "x"},
		OnResult: func(r runner.Result) {
			if r.Err != nil {
				return
			}
			results[r.URL] = struct{}{}
		},
	}

	if err := options.ValidateOptions(); err != nil {
		log.Fatal(err)
	}

	httpxRunner, err := runner.New(&options)
	if err != nil {
		log.Fatal(err)
	}
	defer httpxRunner.Close()

	httpxRunner.RunEnumeration()
	fmt.Println("Results:", results)
}

$ go run .
Results: map[https://projectdiscovery.io:{} https://scanme.sh:{}]

[Mzack9999]

lgtm - I guess the tests is failing due to issues with ASN endpoint issues