LPS-46696 - Prevent unintentional portlet dragging on mobile devices

Hi Jon,

Attached is another update for https://issues.liferay.com/browse/LPS-46696.

1) I *think* this should account for all conditions for when the drag handle should show.  I tried impersonating a lot of different users in different states and everything seemed right.

2) Also I tried to decouple it from the theme as much as I could by moving the styles to generic_portlet.css and allowing the handle class and icon class to be over-writable in the same way navigation.js does it.  But I wasn't sure where exactly it should go. 

Please let me know if there are any issues.

Thanks!