Add more details about the node deployment process, when an instance
is booted by nova. This change covers iscsi and direct deploy methods
with PXE boot. This change also updates the sequence diagrams for
deploy process.
Co-Authored-By: Galyna Zholtkevych <galynazholtkevych1991@gmail.com>
Change-Id: Icaec14d10e702627bab0763e40efa77131564dec