Add(env): Add environment variable to enable remount feature

[payes]

To enable the auto remount feature when the volume goes into read only mode, REMOUNT env can be added to the csi node driver section in csi operator yaml:

kind: DaemonSet
apiVersion: apps/v1
metadata:
  name: openebs-cstor-csi-node
  namespace: kube-system
spec:
  selector:
    matchLabels:
      app: openebs-cstor-csi-node
  template:
    metadata:
      labels:
        app: openebs-cstor-csi-node
        role: openebs-cstor-csi
    spec:
      priorityClassName: system-node-critical
      serviceAccount: openebs-cstor-csi-node-sa
      hostNetwork: true
      containers:
        - name: csi-node-driver-registrar
          image: quay.io/k8scsi/csi-node-driver-registrar:v1.0.1
          imagePullPolicy: IfNotPresent
          args:
            - "--v=5"
            - "--csi-address=$(ADDRESS)"
            - "--kubelet-registration-path=$(DRIVER_REG_SOCK_PATH)"
          lifecycle:
            preStop:
              exec:
                command: ["/bin/sh", "-c", "rm -rf /registration/cstor.csi.openebs.io /registration/cstor.csi.openebs.io-reg.sock"]
          env:
            - name: ADDRESS
              value: /plugin/csi.sock
            - name: DRIVER_REG_SOCK_PATH
              value: /var/lib/kubelet/plugins/cstor.csi.openebs.io/csi.sock
            - name: KUBE_NODE_NAME
              valueFrom:
                fieldRef:
                  fieldPath: spec.nodeName
            - name: NODE_DRIVER
              value: openebs-cstor-csi
          volumeMounts:
            - name: plugin-dir
              mountPath: /plugin
            - name: registration-dir
              mountPath: /registration
        - name: openebs-csi-plugin
          securityContext:
            privileged: true
            capabilities:
              add: ["CAP_MKNOD", "CAP_SYS_ADMIN", "SYS_ADMIN"]
            allowPrivilegeEscalation: true
          image: quay.io/openebs/cstor-csi-driver:ci
          imagePullPolicy: IfNotPresent
          args:
            - "--nodeid=$(OPENEBS_NODE_ID)"
            - "--endpoint=$(OPENEBS_CSI_ENDPOINT)"
            - "--url=$(OPENEBS_CSI_API_URL)"
            - "--plugin=$(OPENEBS_NODE_DRIVER)"
          env:
            - name: OPENEBS_NODE_ID
              valueFrom:
                fieldRef:
                  fieldPath: spec.nodeName
            - name: OPENEBS_CSI_ENDPOINT
              value: unix:///plugin/csi.sock
            - name: OPENEBS_NODE_DRIVER
              value: node
            - name: OPENEBS_API_URL
              value: https://api.openebs.com/
            - name: OPENEBS_MAPI_SVC
              value: maya-apiserver-service
            - name: OPENEBS_NAMESPACE
              value: openebs
            - name: REMOUNT
              value: "true"
          volumeMounts:
            - name: plugin-dir
              mountPath: /plugin
            - name: device-dir
              mountPath: /dev
            - name: pods-mount-dir
              mountPath: /var/lib/kubelet/pods
              # needed so that any mounts setup inside this container are
              # propagated back to the host machine.
              mountPropagation: "Bidirectional"
            - name: iscsiadm-bin
              mountPath: /sbin/iscsiadm
            #Enable the following for Ubuntu 18.04
            - name: iscsiadm-lib-isns-nocrypto
              mountPath: /lib/x86_64-linux-gnu/libisns-nocrypto.so.0
      volumes:
        - name: device-dir
          hostPath:
            path: /dev
            type: Directory
        - name: registration-dir
          hostPath:
            path: /var/lib/kubelet/plugins_registry/
            type: DirectoryOrCreate
        - name: plugin-dir
          hostPath:
            path: /var/lib/kubelet/plugins/cstor.csi.openebs.io/
            type: DirectoryOrCreate
        - name: pods-mount-dir
          hostPath:
            path: /var/lib/kubelet/pods
            type: Directory
        - name: iscsiadm-bin
          hostPath:
            path: /sbin/iscsiadm
            type: File
        #Enable the following for Ubuntu 18.04
        - name: iscsiadm-lib-isns-nocrypto
          hostPath:
            path: /lib/x86_64-linux-gnu/libisns-nocrypto.so.0
            type: File

[codecov-io]

Codecov Report

Merging #56 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #56   +/-   ##
=======================================
  Coverage   53.72%   53.72%           
=======================================
  Files          12       12           
  Lines         631      631           
=======================================
  Hits          339      339           
  Misses        272      272           
  Partials       20       20

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[prateekpandey14]

lgtm