Updating CreatePodArgs to consume PVC args as a map instead of string

[shlokc9]

This PR updates the signature of PVC specific arguments in the following CreatePodArgs;

type CreatePodArgs struct {
	Name           string // Only one of Name or
	GenerateName   string // GenerateName should be specified.
	PVCName        string
	Namespace      string
	RunAsUser      int64
	ContainerImage string
	Command        []string
	ContainerArgs  []string
	MountPath      string // Only one of MountPath or
	DevicePath     string // DevicePath should be specified.
}

from multiple string type variables to a single map[string]VolumePath type variables;

type VolumePath struct {
	MountPath  string // Only one of MountPath or
	DevicePath string // DevicePath should be specified.
}

type CreatePodArgs struct {
	Name           string // Only one of Name or
	GenerateName   string // GenerateName should be specified.
	PVCMap         map[string]VolumePath
	Namespace      string
	RunAsUser      int64
	ContainerImage string
	Command        []string
	ContainerArgs  []string
}

to allow input of multiple PVCs while creating an inspector pod

Tested these code changes by running all the fake tests in the csi package

[bathina2]

LGTM

[bathina2]

nit, please fix before merging