Make basic supply chain example easier to follow

[davidmirror-ops]

By following the basic supply chain example, there are several points of potential confusion for users:

1. Make sure to check out the version of this document in a tag that matches the latest version (for instance, https://github.com/vmware-tanzu/cartographer/tree/v0.0.7/examples). I'm not sure if the wording is clear enough and also the example link could lead to confusion

2. Cartographer, and dependencies used in the example To install cartographer, refer to README.md.

All that cartographer does is choreograph the passing of results from a Kubernetes object to another, following the graph described in the ClusterSupplyChain object.

This means that cartographer by itself is not very useful - its powers arise from integrating other Kubernetes resources that when tied together with a supplychain, forms something powerful.

While these two sentences are true, they are probably better suited for a different location in the doc where we emphasize the value prop. In this section all what users are trying to find is a numbered list of requirements

kpack, for providing an opinionated way of continuously building container images using buildpacks

Somehow it's not clear if this is a requirement or not as the doc has been following a numbered sequence and suddenly there are several unnumbered requirements

source-controller, for providing the ability to find new commits to a git repository and making it internally available to other resources

Probably useful to specify that it's Flux's source-controller

kapp-controller, for providing us with the ability of deploying multiple Kubernetes objects as a single unit

This is part of Carvel tools, so should be in that section