Resolve "weblab link is incorrect"

What does this mr do?

Fixes the WebLab link of a submission. Automatically @tudelft.nl was added to the end of the link but this is removed now.

Actions taken to fix bug

Add a method in UserService to remove the currently selected emailSuffix in application.yaml. Then remove the email suffix whenever the link itself is created in the RequestController.

Does this MR meet the acceptance criteria?

• I have added a changelog entry to reflect the significant changes I made and the bug I fixed.
• A test was created to test the bug.
• I have updated the documentation accordingly.
• I adhere to the style guide.

Closes #187 (closed)