wcst_import supports regex in pre hook's replace_path

[Bang Pham Huu]

Currently, when using pre-hook in wcst_import, one can only replace 1 original input file path with 1 replaced path, e.g:

"replace_path": ["${file:path}.resized"]

However, in case the input file is too big and need to split to smaller tiles, it needs to support this case with a new evaluation expression ${file:directory_path} which points to the folder containing original input file. Then, replace_path can collect split tif files from split folder like this:

"cmd": "gdal_retile.py -targetDir ${file:directory_path}/split/ 
 ${file:path} -ps 20000 20000 -co \"COMPRESS=LZW\" -co \"TILED=YES\"",

"replace_path": ["${file:directory_path}/split/*.tif"]

So 1 original input file will be imported from multiple tile files instead.