Adding a new Scanner (Ikarus)

[Alessandro De Zorzi]

My final working integration for Antivirus Ikarus with Amavis on Linux
Debian system:

### https://www.ikarussecurity.com/
['IKARUS scan.server',
   \&ask_daemon,
   ["GET /virusscan?filename={}/../email.txt HTTP/1.0\r\n\r\n",
'127.0.0.1:80'],
   qr/<status>clean<\/status>/,
   qr/<status>infected<\/status>/,
   qr/<name>(.+)<\/name>/ ],


fix the port the scan server works on in accordance with
/opt/scanserver/conf/scanserver.conf

@developer: please add section as example in @av_scanners if you wish,
near existing 'Ikarus AntiVirus for Linux' section

HTH
Alessandro - Lota