Allow Gramps family tree names to be configured through the `new` project API/command

[bartfeenstra]

Definition of Done

• Update Gramps questions and configuration in betty.project.new.new()
• Ask if the user wants to add a family tree from the local Gramps installation directly
• Ask for any of the newly supported Gramps file formats
• Warn if the Gramps executable cannot be found or if its help command fails