Added CONTRIBUTORS.txt and updated LICENSE (#73)

Author: kvrigor

CONTRIBUTORS.txt

@@ -0,0 +1,9 @@
+Stefan KOLLET
+Paul RIGOR
+Stefan POLL
+Johannes KELLER
+Marco VAN HULTEN
+Ana GONZALEZ-NICOLAS
+Daniel CAVIEDES-VOULLIÈME
+Olga DOMBROWSKI
+

LICENSE

@@ -1,9 +1,9 @@
-Copyright (c) 2020-2021, Paul Rigor, Stefan Kollet
+Copyright (c) 2020-2025, Centre for High-Performance Scientific Computing in Terrestrial Systems (HPSC TerrSys)
 Copyright (c) 2005-2018, University Corporation for Atmospheric Research (UCAR)
 All rights reserved.
 
-Developed by: Paul Rigor, Stefan Kollet
-              https://www.fz-juelich.de/ibg/ibg-3/EN/Home/home_node.html
+Developed by: Centre for High-Performance Scientific Computing in Terrestrial Systems (HPSC TerrSys)
+              https://www.hpsc-terrsys.de/en
 
               University Corporation for Atmospheric Research - National Center for Atmospheric Research
               https://www2.cesm.ucar.edu/working-groups/sewg
@@ -20,7 +20,7 @@ the Software is furnished to do so, subject to the following conditions:
     - Redistributions in binary form must reproduce the above copyright notice, 
       this list of conditions and the following disclaimers in the documentation 
       and/or other materials provided with the distribution.
-    - Neither the names of [Name of Development Group, UCAR], 
+    - Neither the names of [UCAR, HPSC TerrSys],
       nor the names of its contributors may be used to endorse or promote 
       products derived from this Software without specific prior written permission.