refact(size): conversion G to Gi

[prateekpandey14]

fixes the G to bytes to Gi conversion while trasitioning from PVC to CVC storage capacity the way kubernetes handles, by converting to Gi form.
here is the example link for the same https://github.com/kubernetes/kubernetes/blob/master/staging/src/k8s.io/cloud-provider/volume/helpers/rounding.go

Note:
RoundUpSize calculates how many allocation units are needed to accommodate a volume of given size. E.g. when user wants 1500MiB volume, while AWS EBS,GKE etc allocates volumes in gibibyte-sized chunks.
RoundUpSize(1500 * 10241024, 10241024*1024) returns '2'
(2 GiB is the smallest allocatable volume that can hold 1500MiB)

1. PVC yaml

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: claim-csi-123
spec:
  storageClassName: cstor-sparse-auto
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 50G

$ kubectl get pvc
NAME            STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS        AGE
claim-csi-123   Bound    pvc-6ba235b5-2189-4eca-9300-e830c30fc23c   47Gi       RWO            cstor-sparse-auto   30m

$ kubectl get cstorvolume -n openebs
NAME                                       STATUS    AGE   CAPACITY
pvc-6ba235b5-2189-4eca-9300-e830c30fc23c   Healthy   30m   47Gi

Signed-off-by: prateekpandey14 prateekpandey14@gmail.com

[codecov-io]

Codecov Report

Merging #59 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #59   +/-   ##
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  Coverage   53.72%   53.72%           
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  Files          12       12           
  Lines         631      631           
=======================================
  Hits          339      339           
  Misses        272      272           
  Partials       20       20

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[mittachaitu]

@prateekpandey14 for the requested 1G we are giving 9317314 bytes extra is that correct way to do?

[mittachaitu]

changes are good

[vishnuitta]

this PR seems to be making size always in GiB.. but, size can be in other units as well like TiB
Need testcases as well

[vishnuitta]

Noticed that this is how k8s as well is doing same. Hence, approving.
Please add testcases at earliest