Upgrade to Rails 8 and Ruby 3.4.5 (#1)

* Bump Ruby to 3.4.5
* Update dependencies
* Adjust for Rails 8 and Ruby 3.5 API changes
* Mark params strings as mutable in prepapration for frozen strings in Ruby 3.5
* Update test for HTML5 sanitizer
    With Rails 7.1 the HTML5 sanitizer became the default, this breakts this test because the old sanitizer used to delete unpermitted nodes, while the new one returns their content
    The final string is safe, but different then it used to be in Rails 7.0
* Remove direct Turbo tesh helpers require & parallelize tests
* Fix Zeitwerk issues with rails extensions
* Update Resque setup for Redis 5+
* Remove unused views
* Remove GID v1 handler

test/test_helper.rb

@@ -9,11 +9,9 @@ require "webmock/minitest"
 WebMock.enable!
 
 class ActiveSupport::TestCase
-  # FIXME: Why isn't this included in ActiveSupport::TestCase by default?
-  include ActiveJob::TestHelper, Turbo::Broadcastable::TestHelper
+  include ActiveJob::TestHelper
 
-  # FIXME: sqlite3 isn't correctly creating the additional databases per core
-  # parallelize(workers: :number_of_processors)
+  parallelize(workers: :number_of_processors)
 
   # Setup all fixtures in test/fixtures/*.yml for all tests in alphabetical order.
   fixtures :all