Upgrade to Rails 7.1 (+ Ruby 3.3 & Alpine 3.20)

[Ithanil]

Description

Updated Rails from 6.1 to 7.1 and made relevant changes accordingly.
At the same time, Ruby was updated from 3.1 to 3.3, which didn't seem to have any relevant breaking changes, and Alpine was updated from 3.17 to 3.20 to support Ruby 3.3 (although a self-compiled version is used anyway in the Docker builds).

Notes for the Rails upgrade:

1. Studied https://guides.rubyonrails.org/upgrading_ruby_on_rails.html#upgrading-from-rails-6-1-to-rails-7-0 and https://guides.rubyonrails.org/upgrading_ruby_on_rails.html#upgrading-from-rails-7-0-to-rails-7-1
   A few points in the above were relevant:

• Spring needed to be bumped to >3.0.0
• Rails version included in the schema dump, see below
• Development and test environments secret_key_base file changed, production unaffected
• config.autoload_lib
• MemCacheStore and RedisCacheStore now use connection pooling by default (connection_pooling was already used by SL before)

2. Other notable things not mentioned above:

• Redirects to other host now need allow_other_host or an exception will be raised. That is relevant for the redirect on join calls.
• MiniTest is now named Minitest.... (that took me a while)
• The default serializer was YAML before and is now nil (and thus would have to be explicitly specified). I have restored the previous default: config.active_record.default_column_serializer = YAML

3. Changes in default files generated by rails app:update have been reviewed and merged in as appropriate, maintaining any previous non-default configurations in most cases. One setting that has been changed in all files is config.cache_classes replaced by config.enable_reloading with inverted boolean value.

4. The app/schema.rb has been updated with the output of rake db:schema:dump. For Scalelite, the only changes are that the schema now contains the Rails version (7.1) and how timestamp precision is handled (see here for a lengthy discussion).

5. Multiple deprecation warnings that are now appearing in Rails test / Rspec runs are NOT addressed yet. Most of them have to be addressed for a move to 7.2 . I will open a corresponding issue mentioning all the deprecations.

As a result of the upgrades, security support is restored for Rails and also Ruby and Alpine. A further upgrade to Rails 7.2 in the near future will secure support until late 2026.

Testing Steps

• all Rails Tests / RSpecs pass
• basic API calls (create, join, getMeetings, etc.)
• getRecordings / recording playback
• a few rake tasks

More testing by another party would be welcome!

Fixed issues:

#1121