Migrate Zend Modules Away from Importing CSS From `zend_modules/public` Folder

[tywrenn]

A big issue with the Zend Modules right now is that they aren't importing the CSS from the usual public/assets folder or the themes folder. It instead has a public folder filled with CSS and JavaScript that is very outdated. We should not have two areas for CSS so a rework of this is needed. I am unsure of the compatibility of these going into Bootstrap 5, so it's definitely something we should fix.