Rails 7.0 and Ruby 3.2 upgrades

[javierm]

Update: Rails 7.0 will be included in Consul Democracy 2.2.0 (see pull request #5465).

The roadmap to Rails 7.0:

• Start using zeitwerk as an autoloader (done pull request Use Zeitwerk to autoload files #5425).
• Move gems that only provide assets to node packages (done in Replace rails-assets.org with Node.js packages #5423, Bump foundation-sites from 6.6.2 to 6.7.5 #5445, Bump jquery-file-upload from 9.12.5 to 9.34.0 #5447, Bump markdown-it from 9.0.1 to 12.3.2 #5473 and Replace SassC/Libsass with Dart Sass #5477)
• Upgrade sprockets-rails (done in Bump sprockets-rails from 3.2.2 to 3.4.2 #5462)
• The initialjs-rails gem isn't compatible with Rails 7 (removed in pull request Replace initialjs-rails with custom avatar code #5481)

You can check the status of these items in our project's kanban.

The major roadblocks to upgrade to Rails 7.0:

1. The ros-apartment gem isn't compatible with Rails 7; a pull request addressing the main issue (see Fix Rails 7 connection handling rails-on-services/apartment#194) was merged over two years ago, but there haven't been any releases of the apartment gem since then. So far we're monkey-patching the gem.

Regarding Ruby, Consul Democracy 2.2.0 will include Ruby 3.2 (see pull request #5404). We'll probably upgrade to Ruby 3.3 in 2025, once all our gem dependencies support it.