Enable filtering requests per course

Closes #595

What does this mr do?

• Add a UI component in the filter page to enable filtering requests by their course
• Filter requests to be shown by the selected courses

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.