Add ECDSA ciphers for TLSv1.2

[sarisia]

Current nginx template for ssl sites does not have ssl_ciphers for ECDSA server certs + TLSv1.2 so using ECDSA certs results in No common ciphers error in clients.

This PR fixes:

• Add ECDSA ciphers for TLSv1.2
• Drop ciphers for TLSv1.1 and SSLv3 since these protocols are already dropped in fs_overlay/var/lib/nginx-conf/nginx.conf.erb

Partially fixes #302

[SteveLTN]

Thanks! Crazy busy with my work, will check it later!

[SteveLTN]

1.23.0 is released and includes this PR. Thanks for the help!