Resolve "More gentle handling of accessDenieds"

What does this mr do?

This mr makes sure that when users try to access a lab/course to which they are not enrolled, they will get redirected to the enroll page.

Screenshots

before

displays error message

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 #254 (closed)