Usability improvements for legacy users

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Please add this to the appropriate places.

Enable users trying to connect to portal.portal to connect to the portal as intended.

echo “192.168.77.1	portal.portal” >> /etc/hosts
echo “local=/portal/“ >> /etc/dnsmasq.conf

Print a helpful message to users trying to login with username open.

echo “Match User open
        Banner /etc/banner-open” >> /etc/ssh/sshd_config

echo “Dear legacy-user,
login using the user "open" is no longer supported.
Please log in with open-front for opening the front door or open-back for opening the back door
For more information read the documentation at https://wiki.shackspace.de/infrastruktur/portal300
Farewell,
open” >> /etc/banner-open

useradd -r -s /bin/false open