All components that deal with authentication now accept a varargs array
of credentials:

1. CentralAuthenticationSerivce#createTicketGrantingTicket()
2. CentralAuthenticationSerivce#grantServiceTicket() (renew form only)
3. CentralAuthenticationSerivce#delegateTicketGrantingTicket()
4. AuthenticationManager

The use of varargs Credentials provides call compatibility with 3.x
components while supporting the requisite inputs (multiple credentials)
for multi-factor use cases.