LPS-50447 - Migrate Login portlet aui-base javascript

Hi Rob,

Attached is an update for https://issues.liferay.com/browse/LPS-50447.

I implemented the ajaxForm plugin, as well as made small source formatting changes, as Nate requested in https://github.com/natecavanaugh/liferay-portal/pull/2915.  I also tested out the form submit, and everything looks to be working perfectly.  The POST form data and params look exactly the same as on Master.

Please let me know if there are issues.

Thanks