Additional extra arguments for TCP components

[prometherion]

Closes #101.

A new specification key has been introduced as follows.

$: kubectl explain tcp.spec.controlPlane.deployment.extraArgs
KIND:     TenantControlPlane
VERSION:  kamaji.clastix.io/v1alpha1

RESOURCE: extraArgs <Object>

DESCRIPTION:
     ExtraArgs allows adding additional arguments to the Control Plane
     components, such as kube-apiserver, controller-manager, and scheduler.

FIELDS:
   apiServer    <[]string>

   controllerManager    <[]string>

   kine <[]string>
     Available only if Kamaji is running using Kine as backing storage.

   scheduler    <[]string>

Example of usage with a manifest.

apiVersion: kamaji.clastix.io/v1alpha1
kind: TenantControlPlane
metadata:
  name: test
spec:
  addons:
    coreDNS: {}
    konnectivity:
      agentImage: us.gcr.io/k8s-artifacts-prod/kas-network-proxy/proxy-agent
      proxyPort: 30184
      serverImage: us.gcr.io/k8s-artifacts-prod/kas-network-proxy/proxy-server
      version: v0.0.31
    kubeProxy: {}
  controlPlane:
    deployment:
      extraArgs:
        apiServer:
        - --cloud-provider=external
        controllerManager:
        - --cloud-provider=external
      replicas: 1
    ingress:
      enabled: false
    service:
      serviceType: LoadBalancer
  kubernetes:
    admissionControllers:
    - ResourceQuota
    - LimitRanger
    kubelet:
      cgroupfs: systemd
    version: v1.23.1
  networkProfile:
    dnsServiceIPs:
    - 10.96.0.10
    podCidr: 10.244.0.0/16
    port: 6443
    serviceCidr: 10.96.0.0/16