Download and package devfile samples and starter projects in the registry

[johnmcollier]

The v1 devfile registry for Eclipse Che / CRW cached the starter projects associated with each devfile, to reduce overall latency when cloning projects (and to support airgap scenarios). The projects would be converted to a zip archive and packaged on the devfile registry container. The OCI-based devfile registry should do the same, and we should ensure that both starter projects, as well as the projects associated with devfile samples are stored on the devfile registry.

Additionally, as part of the work on the registry viewer, in order to display the sample contents in the UI (e.g. the devfile, logo) the devfile registry needs to provide an API to retrieve the devfile.yaml and logo from devfile samples.

• Download and archive starter projects for each devfile stack during registry build
  • Ensure that references in the devfile to the starter project are updated to reference the local project archive
• Download and archive devfile samples during registry build
• Provide an API for retrieving the devfile.yaml and sample logos from devfile samples

[johnmcollier]

Closing in favour of #516, which has more relevant information

The sample side of this issue had already been covered by devfile/registry-support#61