Improvements on the Background Feature creation process

[ccjmk]

When a player creates a background feature, that feature item is both added to the created Actor, and saved on the Items Directory (for if the DM wants to save it on a compendium for future use, for example), but that flexibility might be more than many games need, and DMs might want to prevent their players from creating background features. Therefore the next changes are planned:

• Add a setting toggle to allow/disable the creation of Background Features from the tool.
• Add a setting toggle for deciding if created Background Features should be saved on the Items Directory or just be transient to the Hero Creation.

[ccjmk]

Deprecating this as I have considered a better approach to strip the custom feature creation from the tool and let users do that externally only.