Updated quickstart doc

I merged "quickstart" doc with "ansible-deployment" and
"deploy-all-in-one-node". All three of them was covering same topic and
added a lot of confusion for new users.

I added some clarification lines from myself, with main goal to recive one
straightforward document for new users.

Change-Id: I793244c47ffbe0ba304e79bacf708494e59d99c4