Update for modern CipherSuites.

Update GPG to configure s2k params.
Update nginx conf to specify more modern ciphersuites, ocsp stapling, https-enforcing CSP & xss protection flags.
Update postfix configuration to specify modern ciphersuites, ecdh support & random source.
Update sshd configuration to specify modern ciphersuites, kex, macs w/ etm, digests.
Create ssh client config matching the servers (host based).

This is a starting point for discussion, upon final agreement some comments at the beginning of the configuration files might have to be adjusted to reflect chosen ciphers.