Resolve "[Queue-2.0] Check Admin overview for todayish courses"

What does this mr do?

Add the admin panel which shows if there are any lab sessions currently ongoing. A calendar is displayed with all the session for the next 7 days, and if currently a session is ongoing an alert is shown!

Screenshots

before

after

Does this MR meet the acceptance criteria?

• I have added a changelog entry to reflect the significant changes I made.
• Tests were created to test the feature.
• I have updated the documentation accordingly.
• I adhere to the style guide.

Closes #404 (closed)