Update to latest SSL config

This adds TLS 1.3, X25519 and the equal preferences cipher config
for ChaCha20.

Author: ghedo

conf

@@ -1,3 +1,4 @@
-ssl_protocols               TLSv1 TLSv1.1 TLSv1.2;
-ssl_ciphers                 EECDH+CHACHA20:EECDH+CHACHA20-draft:EECDH+AES128:RSA+AES128:EECDH+AES256:RSA+AES256:EECDH+3DES:RSA+3DES:!MD5;
+ssl_protocols               TLSv1 TLSv1.1 TLSv1.2 TLSv1.3;
+ssl_ecdh_curve              X25519:P-256:P-384:P-224:P-521;
+ssl_ciphers                 '[ECDHE-ECDSA-AES128-GCM-SHA256|ECDHE-ECDSA-CHACHA20-POLY1305|ECDHE-RSA-AES128-GCM-SHA256|ECDHE-RSA-CHACHA20-POLY1305]:ECDHE+AES128:RSA+AES128:ECDHE+AES256:RSA+AES256:ECDHE+3DES:RSA+3DES';
 ssl_prefer_server_ciphers   on;