Widget.py: Allow to set autocomplete also for hidden fields

We may want to set autocomplete 'off' or whatever other value
18 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-Master

02:05:11

failed ERP5.PerformanceTest-Master

00:43:25

failed ERP5.UnitTest-Master

03:49:12

passed SlapOS.Eggs.UnitTest-Master.Python2

00:15:25

passed SlapOS.Eggs.UnitTest-Master.Python3

00:20:56

passed Wendelin.UnitTest-Master

00:49:37

passed ERP5.CodingStyleTest-Master

00:56:41

passed ERP5.CodingStyleTest-Master

02:36:02

failed ERP5.PerformanceTest-Master

00:40:36

failed ERP5.PerformanceTest-Master

00:40:05

failed ERP5.UnitTest-Master

01:50:18

failed ERP5.UnitTest-Master

04:05:09

passed SlapOS.Eggs.UnitTest-Master.Python2

00:21:14

passed SlapOS.Eggs.UnitTest-Master.Python2

00:14:07

passed SlapOS.Eggs.UnitTest-Master.Python3

00:22:39

passed SlapOS.Eggs.UnitTest-Master.Python3

00:17:33

passed Wendelin.UnitTest-Master

00:36:18

passed Wendelin.UnitTest-Master

00:58:29