Added documentation

cmd/clients.go

cmd/devices.go

cmd/docs.go

cmd/dump.go

cmd/list.go

cmd/ping.go

cmd/root.go

cmd/version.go

docs/udm-query.md

docs/udm-query_clients.md

docs/udm-query_completion.md

docs/udm-query_completion_bash.md

docs/udm-query_completion_fish.md

docs/udm-query_completion_powershell.md

docs/udm-query_completion_zsh.md

docs/udm-query_devices.md

docs/udm-query_dump.md

docs/udm-query_list.md

docs/udm-query_ping.md

docs/udm-query_version.md