Get app working again on letterboxgame.com

• This took a few evenings because 1. The codebase is super old and several libraries need to be updated, and 2. I didn't want to lose the historical game data which is 2.65gb. But it's now back up and working at letterboxgame.com

• Upgrade codebase to rails 7, ruby 3

• Replace actioncable with ably

• Get app running on main VM

• Export database from old DigitalOcean droplet

• Import database into new database

• Reset sequences