Add a 'quick start' guide

- This is a baby step to making this a bit easier for developers with very little understanding of the project to get up and running.
Add links to vcloud walker and extra steps

- Following this quickstart should hopefully get a new user of vcloud-tools a readout of their organization.
- This seems like a good way to kick off before delving into the more detailed documentation below
be clearer about vcloud-walker
Change example to walk networks, for brevity