CCConf was waiting for a logging argument.
Two options were added to choose the user and group running the
cc-server. This was added to put the proper rights on json file if the
user and/or group are not the default ones.

With the permission of Romain Degez, CTO of Smartjog.

Signed-off-by: Sébastien Luttringer <sebastien.luttringer@smartjog.com>