We make a mostly redundant copy of Webpack bundles for prod without
chunkhashes in the file names, so that RequireJS can point to bundles
without having to understand anything about Webpack's optimization.
Meant to unblock EDUCATOR-2357 and PR #17518.

EDUCATOR-1448

Modifies paver webpack task to use production configuration in all
non-devstack environments, and a development config in devstack.