WCST_Import Send UpdateWcsLayer request to WMS handler instead of InsertWcsLayer request when layer already existed

[Bang Pham Huu]

When ingredient file specified with

 "options": {
      "wms_import": true
    }

the last slices of the session will send a InsertWCSLayer to WMS handler to invoke the persisting procedure for storing current WCS coverage as a WMS layer.

However, if run the ingredient file again to update coverage or add the new slices (map mosaic 2D) this request is still the same name: InsertWCSLayer.

In new Petascope, it is specified clearly, InsertWCSLayer for creating new WMS layer and UpdateWCSLayer to update an existing WMS layer with the new dimensions's boundary.

So WMS should check if WMS layer existed or not and send the corresponding request.