LPS-50428 - Migrate Asset Publisher portlet aui-base javascript

Hi Rob,

Attached is an update for https://issues.liferay.com/browse/LPS-50428.

I spent a good amount of time trying to convert over the use of aui-io in select_structure_field.jsp, but I left it out of this pull.  I was able to get most of it to work but there were issues with it's integration into ddm_form.js.  So I think it would be best to not migrate it over until we're ready to migrate liferay-ddm-form as well.

There were several instances where I removed unnecessary checks of nodes existing, and set forms variables instead of referencing them like 'document...fm' over and over.  I also replaced the use of A.Lang.String.escapeHTML with the lo-dash method escape.

Please let me know if there are any issues.

Thanks!