x-header 설정 참고 사이트
https://cyberx.tistory.com/171
https://stackoverflow.com/questions/18337630/what-is-x-content-type-options-nosniff
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Content-Type-Options
https://developer.mozilla.org/ko/docs/Web/HTTP/Headers/X-XSS-Protection
https://webhack.dynu.net/?idx=20161119.001
https://webhack.dynu.net/?idx=20161117.003&print=friendly
https://geekflare.com/secure-apache-from-clickjacking-with-x-frame-options/
https://stackoverflow.com/questions/33172248/nothing-will-unset-x-frame-options-apache-php-5-3
https://m.blog.naver.com/PostView.nhn?blogId=nologout&logNo=220960018798&proxyReferer=https%3A%2F%2Fwww.google.com%2F