www/drogon: New port!

Drogon is a C++17/20 based HTTP application framework. Drogon can be used to
easily build various types of web application server programs using C++.

Drogon supports:

• Non-blocking I/O network lib based on kqueue
• HTTP 1.0/1.1
• Cookies and sessions
• HTTPS
• WebSockets
• JSON/REST
• Compression: brotli, gzip
• HTTP Pipelining
• Asynchronous reading/writing to MySQL/Redis
• and more!