use new ciphers, kex, macs and privilege separation for redhat family 7 or later

[atomic111]

ciphers: https://github.com/dev-sec/tests-ssh-hardening/blob/master/libraries/ssh_crypto.rb#L27

kex: https://github.com/dev-sec/tests-ssh-hardening/blob/master/libraries/ssh_crypto.rb#L60

macs: https://github.com/dev-sec/tests-ssh-hardening/blob/master/libraries/ssh_crypto.rb#L96

privilege separation: https://github.com/dev-sec/tests-ssh-hardening/blob/master/libraries/ssh_crypto.rb#L134