Create group when install package

[ogra]

neither works yet … see:

Multiple users and groups in snaps

The previous (obsolete) discussion on the topic is here. To make the discussion clearer I was asked to start a new topic with the currently agreed to design so that we may work through any additional details. As such, I will copy the entire ‘Introduction’ and a description of the 4 use cases from the other topic, but leave the ‘Implementation Ideas’ in the other topic for historical reference. Introduction Today, snappy’s notion of users (and groups) is primitive: daemons run as root commands…