Add slides on auto and literal types as NTTP

[bernhardmgruber]

I just watched the recording from the essentials course in spring. Apparently, I promised some slides on auto as NTTP. However, I could not come up with a good example in a reasonable amount of time. I will park the effort here as a draft. Feel free to suggest something different!

[stale[bot]]

This issue or pull request has been automatically marked as stale because it has not had recent activity. Please manually close it, if it is no longer relevant, or ask for help or support to help getting it unstuck. Let me bring this to the attention of @klieret @wdconinc @michmx for now.