Set Agent version correctly

[backstreetkiwi]

A running Stackable agent registers a node at the K8s API.
In its metadata, it sets its version to the version of the underlying krustlet. It would be more convenient for us to see the actual stackable-agent version there.
Additionally, we should remove/overwrite the label type so that it does no longer hold the value krustlet which might lead to wrongly scheduled pods if Stackable coexists with other platforms that use the krustlet.

[backstreetkiwi]

This is the result of a kubectl describe ... command that shows the aforementioned properties:

Name:               node-0
Roles:              <none>
Labels:             beta.kubernetes.io/arch=stackable-linux
                    beta.kubernetes.io/os=stackable-linux
                    kubernetes.io/arch=stackable-linux
                    kubernetes.io/hostname=node-0
                    kubernetes.io/os=stackable-linux
                    type=krustlet
Annotations:        node.alpha.kubernetes.io/ttl: 0
                    volumes.kubernetes.io/controller-managed-attach-detach: true
CreationTimestamp:  Wed, 18 Aug 2021 11:23:19 +0200
Taints:             kubernetes.io/arch=stackable-linux:NoExecute
                    kubernetes.io/arch=stackable-linux:NoSchedule
Unschedulable:      false
Lease:
  HolderIdentity:  node-0
  AcquireTime:     Wed, 18 Aug 2021 11:34:15 +0200
  RenewTime:       Wed, 18 Aug 2021 11:34:15 +0200
Conditions:
  Type        Status  LastHeartbeatTime                 LastTransitionTime                Reason                     Message
  ----        ------  -----------------                 ------------------                ------                     -------
  Ready       True    Wed, 18 Aug 2021 11:34:15 +0200   Wed, 18 Aug 2021 11:23:18 +0200   KubeletReady               kubelet is posting ready status
  OutOfDisk   False   Wed, 18 Aug 2021 11:23:18 +0200   Wed, 18 Aug 2021 11:23:18 +0200   KubeletHasSufficientDisk   kubelet has sufficient disk space available
Addresses:
  InternalIP:  10.0.4.75
  Hostname:    node-0
Capacity:
  cpu:                4
  ephemeral-storage:  61255492Ki
  hugepages-1Gi:      0
  hugepages-2Mi:      0
  memory:             4032800Ki
  pods:               110
Allocatable:
  cpu:                4
  ephemeral-storage:  61255492Ki
  hugepages-1Gi:      0
  hugepages-2Mi:      0
  memory:             4032800Ki
  pods:               110
System Info:
  Machine ID:                 
  System UUID:                
  Boot ID:                    
  Kernel Version:             
  OS Image:                   
  Operating System:           linux
  Architecture:               stackable-linux
  Container Runtime Version:  mvp
  Kubelet Version:            0.7.0
  Kube-Proxy Version:         v1.17.0
Non-terminated Pods:          (1 in total)
  Namespace                   Name                                      CPU Requests  CPU Limits  Memory Requests  Memory Limits  Age
  ---------                   ----                                      ------------  ----------  ---------------  -------------  ---
  default                     zookeeper-simple-default-server-node-0    0 (0%)        0 (0%)      0 (0%)           0 (0%)         4m8s
Allocated resources:
  (Total limits may be over 100 percent, i.e., overcommitted.)
  Resource           Requests  Limits
  --------           --------  ------
  cpu                0 (0%)    0 (0%)
  memory             0 (0%)    0 (0%)
  ephemeral-storage  0 (0%)    0 (0%)
  hugepages-1Gi      0 (0%)    0 (0%)
  hugepages-2Mi      0 (0%)    0 (0%)
Events:              <none>