CMFActivity: Allow to disable/enable mail notification

See merge request !1197
6 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-Master

00:59:18

passed ERP5.PerformanceTest-Master

00:30:50

failed ERP5.UnitTest-Master

01:34:37

failed ERP5.UnitTest-Master.Medusa

03:35:33

passed SlapOS.Eggs.UnitTest-Master.Python2

00:49:35

passed SlapOS.Eggs.UnitTest-Master.Python3

00:20:48