arch: POSIX: Add Kconfig option to stop on all faults

Added an option to stop the execution of the posix arch based
executable on the first fault, even if the fault stemmed from a
non essential thread.
Having it fail faster, in the first fault, will ease debugging
in many cases.
The option is disabled by default to preserve the old behavior.

Signed-off-by: Alberto Escolar Piedras <alpi@oticon.com>