Upgrades, add pre upgrade hook, copy release version files

For 5.0.x version we didn't have separate versions
for openstack releases, now we have openstack patching
and it's required for us to know what our system
is consists of. In order to do it, we need to copy
version.yaml files to `/etc/fuel/release_versions/`.

Change-Id: I37b5917eec519ed83531c77d30351811267bc9c2
Related-bug: #1365087
Merge "Upgrades, add pre upgrade hook, copy release version files"