Move predefinded data to be more compatible with catalog systems

git-svn-id: https://radiativetransfer.org/svn/rt/arts-cat-data/trunk@11426 aaf1aab0-4228-0410-ad68-8dceda47f409

ChangeLog

+2024-01-31 Richard Larsson <richard.larsson@uni-hamburg.de>
+
+	* ARTS-CAT-DATA-9
+
+	* Move MT CKD data to predef/ folder and split it in two files
+	The new files should contian the same data but allows the IO
+	via catalog parameters to work more naturally.
+
 2023-12-18 Manfred Brath <manfred.brath@uni-hamburg.de>
 
 	* ARTS-CAT-DATA-8

model/mt_ckd_4.0/README.txt → predef/README.txt

-The H2O.xml data is extracted from a netcdf file distributed via
+This folder is intended to contain data required by ARTS predefined models.  Not all predefined
+models are compatible with each other.  It is therefore intended that this folder is read with
+one of ARTS catalog reading routines from a user-provided list of absorption species models.
+
+NOTE: if a model's data is not in this folder, its data is available inside ARTS pre-compiled
+as a named model.
+
+The H2O-ForeignContCKDMT400.xml and H2O-SelfContCKDMT400.xml data is extracted from a netcdf file distributed via
 https://github.com/AER-RC/MT_CKD/blob/55e0914a6561019e1f847c3b3a6766f88205e496/data/absco-ref_wv-mt-ckd.nc
 
 The original netcdf file has the following metadata (ncdump -h):
@@ -37,4 +44,6 @@ variables:
 		:history = "MT_CKD_4.0: water vapor continuum data is now stored in a netCDF file and the code is in a separate module.For previous versions see (http://github.com/AER-RC/MT_CKD).             " ;
 }
 
-The ARTS H2O.xml file stores all of the variables for use in the ARTS model as they were extracted from the file
+The two ARTS files stores all of the variables for use in the ARTS model as they were extracted from the file.
+Both files should be identical because they define different models but it is still stored this way to be 
+catalog-compatible.