Add a modern profile for SSL policy

TLSv1.0 & TLSv1.1 suffer from [POODLE](blog.qualys.com/ssllabs/2014/12/08/poodle-bites-tls) and other [padding oracle attack](blog.cloudflare.com/padding-oracles-and-the-decline-of-cbc-mode-ciphersuites)
You need to support only TLSv1.2 to expect closing those weakness (and use only AEAD cipher suite in case of padding oracle).

The same, non PFS cipher suite is not at all recommended (see heartbleed effect).
DHE support [is dropped](digicert.com/blog/google-plans-to-deprecate-dhe-cipher-suites) from any decent user agent and can lead to [mitm attack](media.ccc.de/v/32c3-7288-logjam_diffie-hellman_discrete_logs_the_nsa_and_you#t=1357) (arround ~25min in the video) with only one side supporting weak cipher suite.
3DES is deprecated and suffer from [sweet32](sweet32.info)

So I recommend using only the `EECDH+CHACHA20:EECDH+AES` cipher suite, which has [quite good compatibility](cryptcheck.fr/suite/EECDH+CHACHA20:EECDH+AES) and a very better security than the actual cipher suite.

Fix #201
Fix #183
Fix #190
Prepare #180

Co-authored-by: aeris <aeris@users.noreply.github.com>

h5bp/ssl/policy_modern.conf

@@ -0,0 +1,17 @@
+# ----------------------------------------------------------------------
+# | SSL policy - Modern                                                |
+# ----------------------------------------------------------------------
+
+# For services that don't need backward compatibility, the parameters
+# below provide a higher level of security.
+#
+# (!) This policy enfore a strong SSL configuration, which may raise
+#     errors with old clients.
+#     If a more compatible profile is required, use intermediate policy.
+#
+# https://wiki.mozilla.org/Security/Server_Side_TLS#Recommended_configurations
+# https://nginx.org/en/docs/http/ngx_http_ssl_module.html
+
+ssl_protocols TLSv1.2;
+ssl_ciphers EECDH+CHACHA20:EECDH+AES;
+ssl_prefer_server_ciphers on;