Replace sponsor information by link to bareos.com

Instead of maintaining information about sponsors at several places,
information are now only kept at https://www.bareos.com/en/sponsors.html
Therefore information here are replaced by a link to that page.

SPONSORS.md

@@ -1,49 +1,6 @@
-List of companies (in alphabetical order) that helped to improve the Bareos project by funded development.
+Several companies helped to improve the Bareos project by funding parts of the development.
 
-Cardtech
---------
-http://www.cardtech.de
+See https://www.bareos.com/en/co-funding.html for information about funded development.
 
-  * bareos-15.2.2
-    * Secure Erase feature
-      * Allow to define an external program (like wipe or shred.exe) for deleting data in a secure manner. This can be necessary to comply to strict industry standards and government regulations that force organizations to mitigate the risk of unauthorized exposure of confidential corporate and government data.
-
-dass IT GmbH
-------------
-http://www.dass-it.de
-
- * dass IT has participated over years with active development and by providing infrastructure such as servers and the Bareos build system.
-
-Friedrich-Schiller-Universität Jena
------------------------------------
-https://www.uni-jena.de
-
-  * bareos-15.2.4
-    * Improved NDMP support for Bareos
-      * NDMP on Solaris SPARC
-      * NDMP Single File Restore on NetApp
-      * Improved NDMP restores on Isilon
-
-Globalways
-----------
-http://www.globalways.net
-
-  * bareos-16.2.2
-    * Client Initiated Connection
-      * Allow File Daemons to connect to the Director, instead that he Director connects to the clients.
-
-Odiso
------
-http://www.odiso.com/
-
-  * bareos-14.2.2
-    * MS SQL Plugin
-      * Supports restore to file and restore to different database server.
-
-Thomas Magnete GmbH
--------------------
-http://www.thomas-magnete.com/
-
-  * bareos-15.2.3
-    * Allow multiple simultaneous Windows VSS backups.
+See https://www.bareos.com/en/sponsors.html for information about Bareos sponsors.