Retitle quick start to make it more obvious in index

When a new comer looks at the docs launch page the quick start should be
more prominent in the table.

Change-Id: Ie4591e6201e17926d74a8d9a2f50da1cc959e2e7

doc/quickstart.rst

 .. quickstart:
 
-====================================================
-Deployment of Kolla on Bare Metal or Virtual Machine
-====================================================
+===========
+Quick Start
+===========
+
+This guide provides a step by step of how to deploy Kolla on bare metal or a
+virtual machine.
 
 Host machine requirements
 =========================