Fix Bootstrap.js integration issue, breaking the form.io forms

[lane711]

We want to start using some bootstrap.js features in the admin UI

if you add bootstrap.js to the admin theme, it breaks the form.io forms from loading (the forms are used for login, content editing, etc). The forms will not load at all (I don't recall if a console error is produced as a starting point for troubleshooting)

Not sure why this is happening, but it needs to be fixed so that we can make other enhancements to the UI that require bootstrap.js

the reference to a CDN version of bootstrap.js can be added in the Script section in the theme.tsx file