100749: Adopt Log4J-2.15 in KC.war

Contents:
kc.war

Steps to apply:
  1) Shutdown the server (stopKC.sh/stopKC.bat)
  2) Locate the kc.war under <KnowledgeCenter>/runtime/app/kc.war
  3) Delete or rename the old kc.war
  4) Copy the new attached kc.war to the same location.
  5) Start the server (startKC.sh/StartKC.bat)