Advise the use to mount /etc & /var read only for docker usage

Fixing Node Check - 2.1.15 typos

Added missing "=" to master.yaml

Fix typo on README.md

In the remediation of 1.1.11 the flag --enable-admission-plugins was missing a =

read config files from host /etc

I don't see how kube-bench can check the permissions on files unless it has access to them on the host, so I think we need to be mounting the /etc directory from the host

Fix node check 2.1.8

Fix check 1.1.37.

Correct readme for 1.11 example

Signed-off-by: Johannes M. Scheuermann <joh.scheuer@gmail.com>

Fixes https://github.com/aquasecurity/kube-bench/issues/170

Correcting the logic of 1.1.14 for Kubernetes 1.11.

Fixing 1.3.7 on 1.11 master.

Fixing checks 2.2.9 and 2.2.10 on 1.11 nodes.

With multiple test items operator defaults to "and". In case of 1.3.7
the tests check whether --address flag is either set to 127.0.0.1 or not
set at all. Those conditions cannot be met at the same time.

Path to kubelet configuration was accidentally prefixed with a dollar
symbol (probably as a result of copying some other test that used
variable name).
After removing the dollar sign from paths both checks pass on conforming
deployment.

Fix issue with kubelet config and unitfile checks

Also clean up the config file for 1.11 a bit.

The CIS benchmark check for node checks 2 config files for kubelet:
  - kubelet config file (kubelet.conf)
  - kubelet systemd unitfile (10-kubeadm.conf)

The getServiceFiles function gets candidates for kubelet systemd
unitfile and returns valid untifiles.

Update tests for Kubernetes 1.11 - thank you @noqcks! 

* Add a few corrections.

* Add a few corrections to node test file.