Using a new python3 module has never been that easy! So we'll
unapologetically use psutil and don't even worry about whether or not
CentOS supports it (it doesn't)
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Since we archive rpm/deb build script on relocatable package and build
rpm/deb using the script, so align python relocatable package too.
Also added SCYLLA-RELOCATABLE-FILE, SCYLLA-RELEASE-FILE and SCYLLA-VERSION-FILE
since these files are required for relocatable package.