Remove insights.html

[BigSpaceships]

It's not actually on the navbar but it's still accessible at https://csh.rit.edu/membership/insights.html so we should fix it and remove it entirely

[Phourtie-Phour]

@BigSpaceships

I’d like to contribute to your project.
I’ve located the membership/insights.html file.
Before proceeding with its removal, could you kindly confirm if it's necessary to remove it?

If so, may I kindly ask you to assign the task to me?

Thank you very much!

[BigSpaceships]

Closed in #393