Add mountOptions support

[bertinatto]

Fixes #102.

/kind feature
/assign @leakingtapan

[k8s-ci-robot]

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[coveralls]

Pull Request Test Coverage Report for Build 199

• 0 of 15 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.5%) to 50.757%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/driver/node.go	0	15	0.0%

Totals
Change from base Build 198:	-0.5%
Covered Lines:	570
Relevant Lines:	1123

---

💛 - Coveralls

[leakingtapan]

@bertinatto Did you get a chance to test the change? Could you give some details on the testing? Other than this, LGTM.

[bertinatto]

@leakingtapan, I created a volume using this storage class:

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: slow
  annotations:
    storageclass.kubernetes.io/is-default-class: "true"
provisioner: ebs.csi.aws.com
volumeBindingMode: WaitForFirstConsumer
parameters:
  fsType: ext4
mountOptions:
  - noexec

And I verified that the volume was mounted with the option noexec.

[leakingtapan]

/lgtm

[leakingtapan]

We should add unit test for node service to improve the code coverage. Ref #142

Merge the PR to not block the feature