According Linux and UNIX file hierarchies:

• /opt can host misc software packages file
• /srv can host shared data

During D2168 I've thought about that and figured we could sort /srv /opt /data mess like this:

• any service data goes to /srv
• any software not packaged goes to /opt

So /opt/salt should become /srv/<something> for example.

/data should migrate to /srv (I think it's already the case for paas docker role)