erp5_web_renderjs_ui: use the field description as tooltip

Like xhtml style
6 jobs for for_testrunner_1 in 0 seconds
Status Job ID Name Coverage
  External
failed ERP5.UnitTest-Master

01:39:17

passed SlapOS.Eggs.UnitTest-Master.Python2

00:09:29

passed SlapOS.Eggs.UnitTest-Master.Python3

00:12:02

failed ERP5.UnitTest-Master

04:09:34

passed SlapOS.Eggs.UnitTest-Master.Python2

00:25:43

passed SlapOS.Eggs.UnitTest-Master.Python3

00:25:02