Optionally include example documents in project templates

[reckart]

Is your feature request related to a problem? Please describe. When creating a new project from a project template, the user still has to import own documents and start annotating. Some users may perceive this as complicated, in particular if they just want to try out the functionality of INCEpTION. Also, when preparing training material, it can be quite useful to already have ready-made example annotations that users can look at directly.

Describe the solution you'd like Include a switch in the project creation dialog which controls if example documents should be imported when a project is created. By default, this switch should be on. But when the user disables the switch, it should remain disabled - also for future sessions.