Improved suse support building puppetdb / puppetdb-terminus

Rakefile adjusted and rpm spec added

The Rakefile will check where the ruby sitelibdir is on a suse system
The install.rake file has been modified for suse specific locations

working rpm spec file added
systemd support added.

see: 
https://build.opensuse.org/package/show?package=puppetdb&project=home%3Aaboe76%3Abranches%3Ahome%3A-miska-%3Avirtio