Support multiple certificates per user

See merge request !1811
7 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
failed ERP5.CodingStyleTest-Master

00:39:18

passed ERP5.PerformanceTest-Master

00:26:47

failed ERP5.UnitTest-Master

01:47:32

failed ERP5.UnitTest-Zope2

01:33:10

passed SlapOS.Eggs.UnitTest-Master.Python2

00:20:33

passed SlapOS.Eggs.UnitTest-Master.Python3

00:23:19

passed Wendelin.UnitTest-Master

00:48:54