ObjectFormManager::OnSubmit : better log for DBWrite exceptions

[piRGoif]

For now if an exception occurs during DBWrite in the portal form context, we only get a message containing a dict key (either Portal:Error:ObjectCannotBeCreated or Portal:Error:ObjectCannotBeUpdated) :

2022-10-11 02:54:08 | Error   | 4     | Combodo\iTop\Portal\Form\ObjectFormManager::OnSubmit at line 1199 : Error: object cannot be created. Check associated objects and attachments before submitting again this form. | IssueLog |||

With this PR we are now using ExceptionLog (introduced in 3.0.0 with N°4261) to print a log with more info.