B0_driver.ExitSourceDriver exit codes.
See also B0_cli.Exit
build_error indicates a build error.
b0_file_error indicates a b0 file error.
deploy_error indicates a deploy error.
no_b0_file indicates no b0 file could be found.
infos has the infos of Cmdliner.Cmd.Exit.defaults, B0_cli.Exit.ok, B0_cli.Exit.some_error and those above.