Add helper icons (?) to anywhere that is not clear by itself

[jackdkdf]

Bit of an ambiguous ticket and not high priority, the list can be updated after the demo with students happens and we get a better idea of what's not clear

• completion bar (question mark should show that it's "number of correctly answered questions / total number of questions")
• resume button on the course cards listed on the user's homepage
• the ability score and what it means
• other stuff presumably we will find