This would replace our bespoke insiders channel download/install mechanism so we can rely on VS Code to update.

• Create a package.prod.json which contains only that which would differ from the nightly build
• Create a "nightly build" workflow (w/ uploading turned off)
• Use GitHub Environments to control whether a nightly build gets pushed to the Marketplace
• Create a custom build for blob storage that will notify people on our old insiders builds to switch to the new extension
• Remove code for blob storage solution
• Switch over to the new workflow
• Upload the custom VSIX to blob storage
• Make a stable release which would overwrite anyone on the insiders build from blob storage

#17133