The previous work done for RHEL-07-040170 didn't work properly on Ubuntu
16.04 due to the way the /etc/issue.net file is read. The login banner is
now deployed to /etc/motd by default to make it work properly for all
distributions. This also covers the requirements for RHEL-07-010040.
Documentation is included.
Implements: blueprint security-rhel7-stig
Change-Id: I417449837eaecb311abd3fbcda326deba6643886
3fa6fd216f