Added all Section 6 items from Levels 1 & 2

https://benchmarks.cisecurity.org/tools2/ubuntu/CIS_Ubuntu_12.04_LTS_Server_Benchmark_v1.0.0.pdf
Do we need to add something for this step?

`ensure no start links for nfs-kernel-server exist in /etc/rc*.d:`

`rm /etc/rc*.d/S*nfs-kernel-server`