Bring in line with the manifest standardisation in review
I37eff5a13a14564e1adc33eb4f0144d571267617
This:
* Removes the pip-manifest cleanup script and corresponding
README documentation
* Adds a dependency on the manifests element
* Uses the manifests element for manifest location and copy to
build area
* Standardises the manifest naming
Change-Id: I8ab0796a8e19419bf40c1ebc94a7eb04e3ba9180