Package starter projects in offline registry

[mike-hoang]

Which area/kind this issue is related to?

/area registry

Issue Description

This issue is part of the EPIC #329 and focuses on implementing the first stage of the design doc.

Build an offline devfile registry with the following requirements:

• Starter projects need to be packaged with as part of the build
• Devfile needs to reference the offline starter projects during the build

Example:

starterProjects:
  - name: go-starter
+   zip: go-starter-offline.zip
-   git:
-     remotes:
-       origin: https://github.com/devfile-samples/devfile-stack-go.git

[mike-hoang]

Initial approach

• Automate the manual install steps for packaging(ref: https://devfile.io/docs/2.2.0/installation-of-in-cluster-offline-devfile-registry)
• For building, use a similar process to the current build process -- i.e bash scripts

[mike-hoang]

Updated approach

• Use the registry-support build scripts to add all required files to the devfile-index instead of creating a new build script

[mike-hoang]

Resources are now packaged as part of the devfile-index, next step is to create a way for the devfiles to reference the offline resources while also preserving location of the the original

[mike-hoang]

Using the devfileEntriesFile, we can get a list of all the starter projects that can be made offline. The devfiles can also be overwritten with the location of the offline projects as well

[mike-hoang]

Devfiles are now overwritten with the new starter project locations, while leaving the previous ones commented out. Will need to test a few more edge cases for overwriting along with ensuring temp files used for the devfile updating are cleaned

[mike-hoang]

PRs opened for review:
devfile/registry-support#179 - adds the scripts required for offline build
devfile/registry#197 - entry point for creating the registry