tuist migration check-empty-settings

After making .xcconfig files the source of truth for build settings, it's important to ensure that build settings are no longer set to the project. To help with that, Tuist includes a command that fails if the build settings of a project or a target are not empty


--xcodeproj-path, -pRequired. Path to the Xcode project whose build settings will be checked
--target, -tOptional. The name of the target whose build settings will be checked. When not passed, it checks the build settings of the project