Change the way LabelIndexOption is implemented and improve it

https://lists.apache.org/thread.html/e9c9237c5468fd899f693352eb23cc514280df41d0d11ae8e51fac97@%3Cdev.s2graph.apache.org%3E

I hope the LabelIndexOption has changed as suggested in the above link.

LabelIndex option

When creating a label index, create a direction item in the optionos field.

• 'labelIndex' works for both directions.
• If there is no specific option, all of them expect to be true. (store indexEdge, store degree)
• If you want to apply a specific option for a specific direction, specify the direction in 'option'.

Definition

Ex)
in direction: drop indexEdge, drop degree
out direction: store indexEdge, store degree

{
    "out": {
        "method": "drop",
        "storeDegree": false
    }
}