feat: rails 7 upgrade

needed for https://trello.com/c/8js2sprL/358-1d-compliance-two-factor-authentication

based on rails 7 upgrade for gud: https://git.panter.ch/panter/gud-volunteers-platform/-/merge_requests/51/commits

I have decided not to fix rubocop in this MR, but rather leave it as a follow up to have clean git history after merging, so I allowed it to fail temporarily