Use a system INI configuration file to get devices mapping

Use a system INI configuration file to get devices mapping

Instead of specifying a JSON configuration file with CAN devices name, it uses
a mapping configuration file that map a high level device names to a real low level names.

File path is to be specified into the generated source code which is /etc/dev-mapping.conf
for now.

Configuration file uses INI file format and is parsed using inih library cpp wrapper.

Change-Id: Ibde104e76cd78a6cc86f6eec4f66c274b7567d43
Signed-off-by: Romain Forlot <romain.forlot@iot.bzh>