Improved: Add comments to clarify purpose of test security.properties override

Thanks: Gašper Kojek for the initial version of the comment message.

Author: jacopoc

framework/security/src/test/resources/security.properties

@@ -16,9 +16,14 @@
 # specific language governing permissions and limitations
 # under the License.
 ###############################################################################
-####
-# OFBiz Security Settings
-####
+
+##############################################################################
+# Test override of security.properties with non production values.
+# This file shadows framework/security/config/security.properties on the
+# test classpath so that unit tests requiring security settings such as
+# JWT keys can run without the need to generate keys or modify the main
+# security.properties file.
+##############################################################################
 
 # -- Security key used to encrypt and decrypt the autogenerated password in forgot password functionality.
 #    Read Passwords and JWT (JSON Web Tokens) usage documentation to choose the way you want to store this key