* add pack:mac:native target
* workaround macOS Jenkins machine not able to build mac universal image.
* workaround for download-artifact build issue on node14, until DevOps can upgrade node16

* download from SiliconLabs fork by default
* enable Github token to be passed in via --githubToken

0. Proper exit if passed zcl.json file is broken.
1. Make zcl.json files an array.
2. Fix unit tests, which do not pass an array to zcl files.
3. Clean up the API for multi-file loading.
4. Properly propagate array and load the packages.

JIRA: ZAPP-757

JIRA: ZAPP-757

This reverts commit a542f3e7.

* instrument codebase via babel-plugin-istanbul for Cypress
* direct jest report to jest-coverage / cypress report to cypress-coverage 
* combine/display code coverage report from all tests via "npm run report"

BUG:  ZAPP-774

linux:
  "artifactName" is required to produce correct artifact name. otherwise ${os} field is not produced.

mac:
  "afterAllArtifactBuild" is used as a workaround to copy apack.json to the root dir.

BUG: ZAPP-775

Simplicity Studio APIs for componentization tech have changed, so this fixes the
issue of having an API that returns ERROR while it actually succeeds in doing
what it was asked to.