Use k8s mount-utils for checking volume resize

[RomanBednar]

Is this a bug fix or adding new feature?
Refactoring only.

What is this PR about? / Why do we need it?
There was some copy-pasted code from mount utils to get it early. It was needed to check if volume needs resizing.
The code is already released in kuberenes/mount-utils so the copy-pasted code should be removed.

What testing is done?
This is what I did to verify the resize still works fine and did not break:

1. Prepare at least one snapshot of a claim (size 1G in the example)

$ oc get volumesnapshots
NAME                READYTOUSE   SOURCEPVC   SOURCESNAPSHOTCONTENT   RESTORESIZE   SNAPSHOTCLASS   SNAPSHOTCONTENT                                    CREATIONTIME   AGE
claim-1-snapshot    true         claim-1                             1Gi           csi-aws-vsc     snapcontent-20720ba2-4a60-441e-85c7-7691eab875d5   75m            75m
claim-1-snapshot2   true         claim-1                             1Gi           csi-aws-vsc     snapcontent-90b37edb-3c92-4170-b5dc-1de36fc13b30   2m24s          3m3s

2. Create and verify a new larger pvc using a snapshot as a source (can be easily done from dashboard - VolumeSnapshots - details - actions - Restore as new PVC)

$ oc get pvc
NAME                        STATUS    VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
claim-1                     Bound     pvc-8526e671-60da-4ec3-91cd-b64a0a958f7b   1Gi        RWO            gp2-csi        78m
claim-1-snapshot2-restore   Pending                                                                        gp2-csi        76s

$ oc get pvc/claim-1-snapshot2-restore -o yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  creationTimestamp: "2022-02-10T12:04:44Z"
  finalizers:
  - kubernetes.io/pvc-protection
  name: claim-1-snapshot2-restore
  namespace: default
  resourceVersion: "62525"
  uid: 07cdce09-1e33-4652-8b17-1d2d1188a0fa
spec:
  accessModes:
  - ReadWriteOnce
  dataSource:
    apiGroup: snapshot.storage.k8s.io
    kind: VolumeSnapshot
    name: claim-1-snapshot2
  resources:
    requests:
      storage: 5Gi
  storageClassName: gp2-csi
  volumeMode: Filesystem
status:
  phase: Pending

3. create a pod using newly created claim with a mount and verify disk size on node

# lsblk | grep pvc-07cdce09-1e33-4652-8b17-1d2d1188a0fa/mount
nvme2n1     259:6    0     5G  0 disk /var/lib/kubelet/pods/563f6c06-65a1-47e1-9c45-27cd7fd368bd/volumes/kubernetes.io~csi/pvc-07cdce09-1e33-4652-8b17-1d2d1188a0fa/mount

4. verify the size was extended accordingly inside of a pod

$ oc get pvc/claim-1-snapshot2-restore -o json | jq '.status.capacity.storage'
"5Gi"

$ oc exec example3 -- /bin/sh -c 'df -h | grep mnt'
/dev/nvme2n1    4.9G   20M  4.9G   1% /mnt/test

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @RomanBednar. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[RomanBednar]

/assign @wongma7

[RomanBednar]

@wongma7 Hello Matthew, can you please review?

[wongma7]

/ok-to-test
/lgtm
/approve

THX!!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: RomanBednar, torredil, wongma7

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