Getting rid of C exceptions

Getting rid of C exceptions

The goal if to used native C++ exception instead our own SLJL-based C
exceptions:

* this removes the problem of exception conversion between C and C++
  context and the lack of interoperability of SimGrid THROW/TRY/CATCH
  with its C++ counterpart;

* we can still throw exceptions from C;

* but we can't catch exception from C anymore, you should use C++
  instead if order to do that;

Things to do afterwards:

* remove exceptions from the C public APIs;

* restore the multiple usage debugging;

* fix the backtrace code and separate from the exception code in order
  to be able to add backtraces to any exception and get backtraces
  without generating exceptions;

* add support for attaching backtraces to any exception;

* attach context (baktraces and cause) everywhere;