* common_test: Add a failing test to show the SISEGV

Signed-off-by: Simarpreet Singh <simar@linux.com>

* common: Go green by fixing isMaster() to instantiate viper

Signed-off-by: Simarpreet Singh <simar@linux.com>

* common: Inject a seam for getBinariesFunc to be patched-in.

Also adds additional tests to showcase unhappy behaviors.

Signed-off-by: Simarpreet Singh <simar@linux.com>

* common_test: Rename TestIsMaster()

Signed-off-by: Simarpreet Singh <simar@linux.com>

* common: init viper with master config

Signed-off-by: Simarpreet Singh <simar@linux.com>

* common: Add a pre-check if valid yaml is passed but doesn't include master.

Also adds additional tests to showcase unhappy behaviors.

Signed-off-by: Simarpreet Singh <simar@linux.com>

* mod: Upgrade viper to v1.4.0

Signed-off-by: Simarpreet Singh <simar@linux.com>

* common: Refactor node only yaml to a file

Signed-off-by: Simarpreet Singh <simar@linux.com>

* common: Log  when master components are not found

Signed-off-by: Simarpreet Singh <simar@linux.com>

* common_test: Refactor subtests into a table

Signed-off-by: Simarpreet Singh <simar@linux.com>

* issue #348: replace everywhere get<Thing>Files with getFiles

* implement test 2.2.8

* Nit: correct indentation

The indentation looked a bit wonky due to spaces vs tabs; hopefully this corrects it

* add glog flush to write the output to a file

* add glog flush before exit on error and fix code comment

The root command will run node checks and if possible master checks.
I've also added some Makefile targets to improve local testing and improve the documentation.

There are checks for the kubeconfig for both kubelet and proxy which
the current kube-bench implementation does not check for properly.
kube-bench checks the wrong files.

This PR adds support for variable substitution for all the config file
types are that should be checked in the CIS benchmarks.

This PR also fixes a buggy in CIS 1.3.0 check 2.2.9, which checks for
ownership of the kubelet config file /var/lib/kubelet/config.yaml but
recommends changing ownership of kubelet kubeconfig file
/etc/kubernetes/kubelet.conf as remediation.

Made all the warnings to be logged and not printed, so when using the json flag the output will be only in json format.

fix #217

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.

If people are trying to use the Docker image to check their cluster, there's a
big likelyhood of them hitting the error message saying that either `kubectl`
or `kubelet` need to be found in order for `kube-bench` to be able to determine
the Kubernetes version in use.

This adds a tip that the version can be specified manually with the `--version`
flag which is a lot easier than having to make a new Docker image with the
right version of `kubelet`/`kubectl` in order for `kube-bench` to work.

This change unifies all config files, podspecs and unitfiles under
a single component configuration key; `config`.

improve error messages.

The server version is used to load the correct benchmark check
to run against the Kubernetes cluster.

Reorder YAML to make a bit more sense. Allow for optional components, and a config file that we don’t think exists.