Frontend rename of unfulfilled to 'Not Taught' and done check into 'completed'. Plus hide delete.

Staff/Instructor Dashboard:

- Change the yellow “unfulfilled” to say “Not Taught” à if possible, make this symbol X or something like that
- Hide the current Delete (red box with red x) from the staff instructor interface
- For the staff interface add words to the symbols: Not Taught / Completed (the green check mark)