Redesign the CommandHandler to contain the supported command types
Rename AddCommandHandler to RegisterCommandHandler
Rename AddDefaultCommandHandlers to SetupDefaultCommandHandlers
Extract the DefaultCommandHandler to a separate concrete class
Extract the command processing logic to a separate method
Add the 'help' command
Remove TODO. It was done in the previous commit
Fix typo
Extract the board drawing logic to a BoardRenderer class
Add some comments
Add TODO item