Add files to the apk in sorted order, to avoid reproducibility issues.

We do that by adding support for a no_containers target which defines
the new option var/container/global_disable in rbm.conf. We already had
the option var/container/use_container doing something similar to this
new option, however it can not be overriden in rbm.conf as we define it
in each project's configuration, which has priority over rbm.conf.

Versions bump and Changelog update