added setup-debian.sh

Copy of Lowendbox's script for backup when their site goes down.

https://raw.githubusercontent.com/lowendbox/lowendscript/master/setup-debian.sh
# wget --no-check-certificate
https://github.com/lowendbox/lowendscript/raw/master/setup-debian.sh
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# bash setup-debian.sh system
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# bash setup-debian.sh exim4
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# bash setup-debian.sh nginx
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# bash setup-debian.sh mysql
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# bash setup-debian.sh php
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# bash setup-debian.sh wordpress blog.example.com
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