refactor(crd): move CR from openebs.io to zfs.openebs.io (#70)

Changed the group name from openebs.io to zfs.openebs.io.

Now ZFS Volume CR will look like this : 
```
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: zfszvolumes.zfs.openebs.io
spec:
  group: zfs.openebs.io
  version: v1alpha1
  scope: Namespaced
  names:
    plural: zfsvolumes
    singular: zfsvolume
    kind:ZFSVolume
    shortNames:
    - zfsvol
    - zv
```

Snapshot CR will look like this :
```
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: zfssnapshots.zfs.openebs.io
spec:
  group: zfs.openebs.io
  version: v1alpha1
  scope: Namespaced
  names:
    plural: fssnapshots
    singular: zfssnapshot
    kind: ZFSSnapshot
    shortNames:
    - zfssnapshot
    - zfssnap

```


Signed-off-by: Pawan <pawan@mayadata.io>

pkg/apis/openebs.io/zfs/v1alpha1/zfsvolume.go

@@ -0,0 +1,127 @@
+/*
+Copyright © 2019 The OpenEBS Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package v1alpha1
+
+import (
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+// +genclient
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
+// +resource:path=zfsvolume
+
+// ZFSVolume represents a ZFS based volume
+type ZFSVolume struct {
+	metav1.TypeMeta   `json:",inline"`
+	metav1.ObjectMeta `json:"metadata,omitempty"`
+
+	Spec VolumeInfo `json:"spec"`
+}
+
+// MountInfo contains the volume related info
+// for all types of volumes in ZFSVolume
+type MountInfo struct {
+	// FSType of a volume will specify the
+	// format type - ext4(default), xfs of PV
+	FSType string `json:"fsType"`
+
+	// AccessMode of a volume will hold the
+	// access mode of the volume
+	AccessModes []string `json:"accessModes"`
+
+	// MountPath of the volume will hold the
+	// path on which the volume is mounted
+	// on that node
+	MountPath string `json:"mountPath"`
+
+	// ReadOnly specifies if the volume needs
+	// to be mounted in ReadOnly mode
+	ReadOnly bool `json:"readOnly"`
+
+	// MountOptions specifies the options with
+	// which mount needs to be attempted
+	MountOptions []string `json:"mountOptions"`
+}
+
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
+// +resource:path=zfsvolumes
+
+// ZFSVolumeList is a list of ZFSVolume resources
+type ZFSVolumeList struct {
+	metav1.TypeMeta `json:",inline"`
+	metav1.ListMeta `json:"metadata"`
+
+	Items []ZFSVolume `json:"items"`
+}
+
+// VolumeInfo contains the volume related info
+// for all types of volumes in ZFSVolume
+type VolumeInfo struct {
+	// OwnerNodeID is the Node ID which
+	// is the owner of this Volume
+	OwnerNodeID string `json:"ownerNodeID"`
+
+	// poolName specifies the name of the
+	// pool where this volume should be created
+	PoolName string `json:"poolName"`
+
+	// SnapName specifies the name of the
+	// snapshot where this volume should be cloned
+	SnapName string `json:"snapname,omitempty"`
+
+	// Capacity of the volume
+	Capacity string `json:"capacity"`
+
+	// RecordSize specifies the record size
+	// for the zfs dataset
+	RecordSize string `json:"recordsize,omitempty"`
+
+	// VolBlockSize specifies the block size for the zvol
+	VolBlockSize string `json:"volblocksize,omitempty"`
+
+	// Compression specifies if the it should
+	// enabled on the zvol
+	Compression string `json:"compression,omitempty"`
+
+	// Dedup specifies the deduplication
+	// should be enabled on the zvol
+	Dedup string `json:"dedup,omitempty"`
+
+	// Encryption specifies the encryption
+	// should be enabled on the zvol
+	Encryption string `json:"encryption,omitempty"`
+
+	// KeyLocation is the location of key
+	// for the encryption
+	KeyLocation string `json:"keylocation,omitempty"`
+
+	// KeyFormat specifies format of the
+	// encryption key
+	KeyFormat string `json:"keyformat,omitempty"`
+
+	// Thinprovision specifies if we should
+	// thin provisioned the volume or not
+	ThinProvision string `json:"thinProvision,omitempty"`
+
+	// VolumeType specifies whether the volume is
+	// zvol or a dataset
+	VolumeType string `json:"volumeType"`
+
+	// FsType specifies filesystem type for the
+	// zfs volume/dataset
+	FsType string `json:"fsType,omitempty"`
+}