Rename @discobot's start new user command

I think what we really need is a one-click link that sends the discourse narrative bot new user tutorial message to the user.

This opens so many possibilities. For example, the %{new_user_tips} template can now append a new line at the bottom if the narrative bot is enabled. It would look like:

For a few quick tips on getting started as a new user, check out this blog post.

As you participate here, we’ll get to know you, and temporary new user limitations will be lifted. Over time you’ll gain trust levels that include special abilities to help us manage our community together.

For even more tips, click to start our interactive new user tutorial.