context: add variables_handler for setup of variables
context: add variables_handler for setup of variables

The launch_and_wait_variables_handler is collecting the RAUC_* variables
from the started subprocess into an hashtable. This way, the caller can
pick necessary variables and e.g. adapt its context or config.

Signed-off-by: Michael Grzeschik <56a917ffddddef251f53499c2bdc20635fcae7f7@pengutronix.de>

rauc/rauc,jluebbe/rauc,ejoerns/rauc,ejoerns/rauc,rauc/rauc,ejoerns/rauc,rauc/rauc,jluebbe/rauc,jluebbe/rauc