[docs][kayobe] Architecture, terms used

Dear Kayoube documentation, If possible please be bit more specific at few points - document Architecture, section Networks refers to bare metal overcloud hosts, however the chapter "Hosts in the System" presents only bare metal compute hosts, nor any other text passage clarifies the term "overcloud". This way it is hard to get full understanding of term "Overcloud out-of-band network". Furthermore, if you talk about an out-of-band stuff it gets hard to see what is out-of-band without term in-band be precisely clear.