cqrs: move query slide before command slide
cqrs: add slide about commandhandlers
cqrs: ignore the dev folder
cqrs: add project for commandHandler implementation
cqrs: add notes on buses
cqrs.commandHandler: add IBus and implementation
cqrs.commandHandler: copy in entity pocos
cqrs.commandHandler: add saveCandidateCommand
cqrs.commandHandler: add dapperExtensions, and my extension methods
cqrs.commandHandler: implement IKeyed
cqrs.commandHandler: add ICommandHandler and implement SaveCandidateCommandHandler
cqrs.commandHandler: move upsert to infrastructure.extensions
cqrs: add commandHandlerRegistry