Resolve "Client side validation for course creation"

What does this mr do?

This mr adds a client-side validation of course creation. It also restyles the course creation page to be simpler and more clean. Course code: Letters and numbers, no spaces Course name: Letters and spaces Submission url: Urls Teacher NetID: Only numbers

Screenshots

Before

After

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 #270 (closed) Closes #271 (closed)