fix: update nginx configuration for SSL support and redirect

[ronibhakta1]

This pull request updates the Nginx configuration and Docker Compose setup to enable HTTPS support using Let's Encrypt certificates. The changes ensure that both HTTP and HTTPS traffic are properly handled, with automatic HTTP-to-HTTPS redirection and improved security headers.

Nginx HTTPS enablement and security improvements:

• Added HTTPS support in Nginx by listening on port 443 and configuring SSL certificates from /etc/letsencrypt (nginx/templates/20-speech-server.conf.template).
• Implemented automatic HTTP-to-HTTPS redirection for the main domain (nginx/templates/20-speech-server.conf.template).
• Enhanced security by adding the Strict-Transport-Security header to enforce HTTPS (nginx/templates/20-speech-server.conf.template).

Docker Compose adjustments for HTTPS:

• Exposed port 443 in the Nginx service and mounted the /etc/letsencrypt directory as read-only to provide SSL certificates (docker-compose.yml). [1] [2]