added multipart upload file,

it works, but need some adjustements,
refactoring and testing

multipart_request.txt

@@ -0,0 +1,53 @@
+POST /upload HTTP/1.1
+Host: localhost:4040
+Connection: keep-alive
+Content-Length: 364
+Cache-Control: max-age=0
+sec-ch-ua: "Chromium";v="104", " Not A;Brand";v="99", "Google Chrome";v="104"
+sec-ch-ua-mobile: ?0
+sec-ch-ua-platform: "Windows"
+Upgrade-Insecure-Requests: 1
+Origin: http://localhost:4040
+Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryeIV4xrEzThmNUcJf
+User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.0.0 Safari/537.36
+Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
+Sec-Fetch-Site: same-origin
+Sec-Fetch-Mode: navigate
+Sec-Fetch-User: ?1
+Sec-Fetch-Dest: document
+Referer: http://localhost:4040/upload_form.html
+Accept-Encoding: gzip, deflate, br
+Accept-Language: fr-FR,fr;q=0.9,en-US;q=0.8,en;q=0.7
+dnt: 1
+sec-gpc: 1
+
+------WebKitFormBoundaryeIV4xrEzThmNUcJf
+Content-Disposition: form-data; name="upload_file"; filename=".gitignore"
+Content-Type: text/plain
+
+.DS_Store
+Thumbs.db
+*.o
+*.d
+*.swp
+*.out
+*.exe
+*.stackdump
+*.a
+*.so
+*.dSYM
+.vscode
+*.lnk
+*.zip
+
+builds
+
+ubuntu_tester
+ubuntu_cgi_tester
+webserv
+!**/webserv/
+*.log
+
+large.jpg
+
+------WebKitFormBoundaryeIV4xrEzThmNUcJf--