Add endpoint to detect DNS over HTTP supports.

[righettod]

Hi,

This PR add the endpoint exposed when the target supports DNS over HTTP requests.

📖My sources were the following ones:

• https://developers.cloudflare.com/1.1.1.1/encryption/dns-over-https/make-api-requests/
• https://github.com/projectdiscovery/nuclei-templates/blob/main/http/miscellaneous/detect-dns-over-https.yaml

👀If the target supports DNS over HTTP then, the behavior should be the following to an HTTP GET (the HTTP 400 is normal because the accept request header to application/dns-json is missing) :

👀Otherwise an HTTP 404 should be obtained:

😉Thanks in advance.