Support filePaths in wcst_import

[Dimitar Misev]

The format parameters of decode allow specifying filepaths as follows:

  // Absolute path to input file(s). This improves ingestion performance if the data 
  // is on the same machine as the rasdaman server, as the network transport is bypassed;
  // It is possible that a format could have multiple files associated to each other,
  // so this argument is an array of filepaths.
  // Note: supported for netCDF, GRIB, and GDAL formats.
  "filePaths": [ "/path/to/file.tif", ... ],

It would be good to make use of this option in wcst_import when the conditions are right (data on same machine as rasserver): we'll save quite some data reading / copying / writing.