feat: use /etc/default/noderig to retrieve default config #5
Description
It is impossible to install noderig if another software already listen on port 9100 due to the default configuration.
It appears that the installation package read the file /etc/default/noderig (https://github.com/ovh/noderig/blob/master/debian/noderig.postinst#L7 and https://github.com/ovh/noderig/blob/master/debian/noderig.postinst#L49).
So, if the file exists it may load the variable START_ON_INSTALL in order to know if it should launch the application.