[swagger specs](https://swagger.io/docs/specification/describing-responses/) requires each response to have a description. Otherwise, ignorable error will be generated. This PR makes sure that description field is not omitted in the event that user did not give a description.
create sub packages
delete unused code
delete code from not use command cmdRouter,cmdTest, cmdRundocs
make command plugins
check with gosimple,staticcheck,go vet,unused,unconvert