Added image utils

Added set of image utilities so as to make
it possible to deal with images when they are
available via http or when they are local files,
when they are packed into containers or not, etc.

Change-Id: Id03f6bcaed2a61b4c6d644675ef4cfeb353258a9
Implements: blueprint image-based-provisioning
Split parser's logic from utils

This is needed for the better code reusage for functional tests.

Change-Id: Ibd499ff3b0efd0c4c529a6957b9c1d89cd895286
Modified fuel_agent_ci

Change-Id: If371eb8d3e1dceae37ad5965c9ea8ca3e336fa94
Implements: blueprint image-based-provisioning
Initial Functional Tests

Add functional tests for fuel_agent

Change-Id: Ic6739ff9c20547c5d9ab2b4fe9dec45bd5742db9