fix reload issue by returning new configuration to the signal loop
example: run crowdsec, disable agent in the config file, reload config.
Now there is no agent but the signal loop believes there is, so
triggering a reload configuration again will make the process hang
forever.
This commit updates the configuration in the signal loop with the one
returned by the signal handler.
* update for making it work with systemd
* take DB_BACKEND from file name; reduce duplicated code; configure db_type=sqlite
* define PACKAGE_TESTING
Co-authored-by: sabban <15465465+sabban@users.noreply.github.com>
Co-authored-by: mmetc <92726601+mmetc@users.noreply.github.com>
