Enable flexible custom workflow steps

It should be possible for the Admin to define on client level a client-specific workflow by

• Adding workflow steps between, before or after the current default steps
• Each step will automatically be set to open, if its preceding steps are set to finished
• For each step the assigned users get an automated mail, when their step is set to open and after assignment.
• Automated mails for the entire workflow can be deactivated in system configuration, what can be overwritten on client and task level
• Templates for the automated mails can be defined on client level. If not, a standard template is used.