Merge branch 'update-and-cleanup' into 'main'

.rubocop.yml

.tool-versions

Dockerfile

Gemfile

Gemfile.lock

app/controllers/application_controller.rb

app/controllers/assignments_controller.rb

app/controllers/candidates_controller.rb

app/controllers/filedrop_files_controller.rb

app/controllers/sessions_controller.rb

app/jobs/pretalx/import_job.rb

app/jobs/republica_2023_or_later/import_job.rb

app/jobs/telegram_group_chat_notification_job.rb

app/jobs/telegram_notify_upcoming_job.rb

app/models/assignment.rb

app/models/conference.rb

app/models/filedrop_file.rb

app/models/session.rb

app/models/session_speaker.rb

app/models/stage.rb