feat(region,host): create disk from existing path (#14677)

Server create disk from existing path.

Usage:

climc server-create --disk storage=<storage>:existing_path=<path> ...
climc disk-create storage=<storage>:existing_path=<path> DISKNAME

Signed-off-by: wanyaoqi <d3lx.yq@gmail.com>

pkg/cloudcommon/cmdline/parser.go

@@ -185,6 +185,8 @@ func ParseDiskConfig(diskStr string, idx int) (*compute.DiskConfig, error) {
 			diskConfig.Storage = str
 		case "image", "image_id":
 			diskConfig.ImageId = str
+		case "existing_path":
+			diskConfig.ExistingPath = str
 		default:
 			return nil, errors.Errorf("invalid disk description %s", p)
 		}