Fixes #37102 - webpack 5

Fixes #36936 - Switch to terser

Refs #35890 - revert enable harmony mode with Uglifier to use ES6 syntax

This reverts commit d590d56578e3d70972efe5138558fd9007140a93.

Fixes #35890 - enable harmony mode with Uglifier to use ES6 syntax

Added some ES6 features across multiple pages to show that everything works

Fixes #35593 - Use CentOS 8 Stream for container

Currently the container image is based on Fedora 33, but that's long
EOL. Current Fedora versions have Ruby 3.1, but we're unable to use
that. Changing it to CentOS 8 Stream is the closest match and also close...

Fixes #35376 - Allow additional entries in config.hosts
Co-authored-by: Ewoud Kohl van Wijngaarden <ewoud@kohlvanwijngaarden.nl>

Fixes #35403 - disable public_file_server in production

Refs #35428 - Simplify i18n.fallbacks handling

This reverts commit 11bfc142561f1c69d2b8b5abc66df943a66b1672. Since
Rails 6.0 the value true is interpreted as `[I18n.default_locale]`
([Rails commit]). ActiveSupport 6.1 also pulls in at least version 1.6
so the specific requirement is also not needed....

Fixes #33851 - cleanup Bullet config

Fixes #31742 - enable eager_load in dev environment