What does this mr do?

Whenever visiting the labs of a course, they are now sorted by opening time instead of creation time. This make it way more intuitive to use and see what labs will be happening next.

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 #314 (closed)