Update wst_id handling:
1. Save INSI in to dssat_wst_id instead of wst_id
2. Use weather file name as the wst_id
Update wst_id handling:
Just use first 4-bit of weather file name as the wst_id
Update wst_id handling:
No longer append wst_id into wst_name
Update wst_id handling:
No longer append wst_id into wst_name