Implement the 'config print' command

[xmudrii]

What this PR does / why we need it:

This PR implements the config print command which prints an example configuration manifest. The command takes flags used to customize the configuration manifest.

List of available flags:

Flags:
  -n, --cluster-name string          cluster name
      --deploy-machine-controller    deploy kubermatic machine-controller (default true)
      --enable-dynamic-audit-log     enable DynamicAuditLog
      --enable-metrics-server        enable metrics-server (default true)
      --enable-pod-security-policy   enable PodSecurityPolicy
  -h, --help                         help for print
  -k, --kubernetes-version string    Kubernetes version (default "1.14.1")
  -p, --provider string              cloud provider name (aws, digitalocean, gce, hetzner, packet, openstack, none) (default "aws")

Command description:

Print an example configuration manifest. Using the appropriate flags you can customize the configuration manifest.
For the full reference of the configuration manifest check the config.yaml.dist manifest
https://github.com/kubermatic/kubeone/blob/master/config.yaml.dist

Usage:
  kubeone config print [flags]

Examples:
kubeone config print

Example:

kubeone config print -n kubeone --enable-pod-security-policy --kubernetes-version 1.14.1

apiVersion: kubeone.io/v1alpha1
kind: KubeOneCluster
name: kubeone
versions:
  kubernetes: 1.14.1
cloudProvider:
  name: aws
features:
  podSecurityPolicy:
    enable: true

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #254

Release note:

Implement the 'config print` command for printing example configuration manifest

/assign @kron4eg

[kron4eg]

/lgtm
/approve

[kubermatic-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: kron4eg

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[kubermatic-bot]

LGTM label has been added.

Git tree hash: 2ce3d3d0119a710d3c849ead6915b103c5d2b6b5

[kron4eg]

/retest

[kron4eg]

/override pull-kubeone-e2e-aws-conformance-1.13.5
/override pull-kubeone-e2e-aws-upgrade-1.13.5-1.14.1

[kubermatic-bot]

@xmudrii: The following tests failed, say /retest to rerun them all:

Test name	Commit	Details	Rerun command
pull-kubeone-e2e-aws-conformance-1.13.5	c272b3f	link	/test pull-kubeone-e2e-aws-conformance-1.13.5
pull-kubeone-e2e-aws-upgrade-1.13.5-1.14.1	c272b3f	link	/test pull-kubeone-e2e-aws-upgrade-1.13.5-1.14.1

Full PR test history

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[kubermatic-bot]

@kron4eg: Overrode contexts on behalf of kron4eg: pull-kubeone-e2e-aws-conformance-1.13.5, pull-kubeone-e2e-aws-upgrade-1.13.5-1.14.1

In response to this:

/override pull-kubeone-e2e-aws-conformance-1.13.5
/override pull-kubeone-e2e-aws-upgrade-1.13.5-1.14.1

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.