The dummy.c was a de-facto default configuration. Rename it to
default-configuration.c. Use unlimited objects and the stack checker.
This makes it easier for new RTEMS users which will likely use this file
if they just work with the usual main() function as the application
entry point. Provide proper arguments for main() using the BSP command
line. Add spare user extensions and drivers.
Do not initialize the network by default. Delete bspinit.c.
