Show number of notes/exams over the tabs inside a course page

Summary

As a user, I want to be able to see the number of notes and exams, so I can better plan my studying spree.

Acceptance Criteria

• Add the note and exam count as a badge on top of their respective tab buttons in the course (1) page
• Add "Empty" as the content of the badge if the resource category (note, exam) is empty, and disable the tab button
• If one tab is empty and the other isn't on page navigation, then auto switch to the tab with resources. If both are empty, show this message: "No resources were found for this course".