With addition of events there will be alot of callbacks.
To avoid having to add many APIs to register callbacks,
provide them all at once in a big table

* src/qemu/qemu_driver.c: Pass in a callback table to QEMU
  monitor code
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor.h Replace
  the EOF and disk secret callbacks with a callback table