Added the ability to specify the SSL key type (ECDSA or RSA) for each site in the Nginx Proxy Manager. This enhancement is particularly useful for environments with IoT devices that have limitations with specific key types, such as RSA-only support. The implementation includes:
- Backend support for storing and validating the `ssl_key_type` field.
- Swagger schema updated to validate the new input.
- Frontend update to allow users to select the SSL key type via a dropdown menu.
This feature ensures greater flexibility and compatibility in managing SSL certificates for diverse setups.
