Created_by link

[s-schumann]

Add created_by model entity linking user, device, context to the consumer that created it.

• Add to data model
• Update database
• Link it in model (dependencies)

current_consumer.email can be used (if not extended by user name)

From #58 (will be closed)

[s-schumann]

Open only to add to controllers to set the same way uuid is set.

Sample: _@user.created_by = currentconsumer.email

[s-schumann]

created_by used, updated when not set to last consumer that updates. Can be closed.