Improve CLI commands (#34973)

Improve help related commands and flags and add tests

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

cmd/keys.go

@@ -19,6 +19,7 @@ import (
 var CmdKeys = &cli.Command{
 	Name:        "keys",
 	Usage:       "(internal) Should only be called by SSH server",
+	Hidden:      true, // internal commands shouldn't not be visible
 	Description: "Queries the Gitea database to get the authorized command for a given ssh key fingerprint",
 	Before:      PrepareConsoleLoggerLevel(log.FATAL),
 	Action:      runKeys,