RTL fix for VE's link widget

The purpose is to flip the direction of the input inside
the link widget for RTL wikis, but flip it again to LTR
if the user inserts an external URL. This is my first VE
fix, I tried to follow conventions and avoid touching the
parent objects that are unrelated to URLs.

Bug: 47717
Change-Id: Ic13b9c3b155ce2979298cac9518c7419b9d45bac
Merge "RTL fix for VE's link widget"