For the parts of the simulator which are dedicated for the native
platforms (POSIX arch based):
* Refactor the parts that interacts with the host, so it is possible to
use it also with embedded libCs
* Enhance it with more options to allow:
* Keeping the content just in RAM
* Erasing the EEPROM file at exit
* Clearing the file at boot
* Also show in the command line help the default file name.
As part of this:
* Update the kconfig dependencies, so we allow building it with other
C libraries in the native targets
* Update the table in the native_sim docs to indicate all C libraries
are supproted now
Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>