Change the default hint implemenation to Python

This only affects drawing hints, JS is still used if possible to
actually click them.

It seems like for many people, the JS implementation was a lot slower
than the Python one...

qutebrowser/config/configdata.py

@@ -932,7 +932,7 @@ def data(readonly=False):
                  valid_values=typ.ValidValues(
                      ('javascript', "Better but slower"),
                      ('python', "Slightly worse but faster"),
-                 )), 'javascript'),
+                 )), 'python'),
              "Which implementation to use to find elements to hint."),
 
             readonly=readonly