GUACAMOLE-2139: Migrate all license information to new automated format.

doc/licenses/cas-client/NOTICE

@@ -0,0 +1,9 @@
+# Name:    Java Apereo CAS Client
+# URL:     https://www.apereo.org/projects/cas
+# From:    'Apereo Foundation' (https://www.apereo.org/)
+# License: Apache v2.0
+#
+# --- BEGIN LICENSE FILE ---
+This project includes:
+  Jasig CAS Client for Java - Core under Apache License Version 2.0
+# --- END LICENSE FILE ---