Refactor FM Debugger to support any debugger implementation like Dbgp.

Here a big refactoring about FM Debugger to support any implentation for FM debugger (RMI, Dbgp, etc).
The basic idea is to set the debugger service in the Configuration (inject the well debugger service, instead to use a static instance).

I do this patch in order to we can discuss easier about "how to manage any debugger service implementation". If you don't like my patch, don't hesitate to tell me.

Note that this patch break the creation of RMI debugger RmiDebuggerService when freemarker.debug.password is found. We could discuss about that (perhaps to use SPI services to register implementation of debugger service).

This patch is the first step to integrate Dbgp debugger (I will do other patch when we will able to support any debugger service).