Oracle install

Updated documentation for oracle installation and wrote a little shell script to install oracle. 

I guess this is the best option as:
1. If I use gradle to install oracle then the code gets clumsy because a lot of env-variables and different unix accounts are involved (this is not really supported in gradle).
2. .. or if I use vagrant/chef to install during vm creation then the vm creation depends on the manual oracle download (even if I do not use/need oracle).