Remove magento-cloud build command

[joeshelton-wagento]

magento-cloud build

This command has always been problematic due to people mistakenly thinking it was a necessary part of local setup. Running the command is quite detrimental to a local installation of a Magento Cloud project due to the symlinks and other changes. To this day, people continue to be roadblocked by it: https://magento.stackexchange.com/questions/364313/magento-cloud-local-installation-issues

Previously, the argument for keeping the command (which always did more harm than good, imho) was that the build process could be demonstrated or tested outside of a Cloud environment. Now that Magento Cloud Docker is available, magento-cloud build is a poor substitute for a better tool. It is vestigial and should be removed.