Add Factory (Generator/Cloner) toggle button to StoryItemOptions

[birbilis]

Version: 0.6.0

Being ableo to set a StoryItem as a Factory (Generator/Cloner) item that can produce a draggable clone of itself when clicked, would allow for making activities where the user designs something by dragging clones of premade (probably anchored) items from a side-palette.

In game-like activities, if dragged "player" falls into a trap (recycle bin item - see #244) and is removed from the Story, then one could drag another instance from an anchored player avatar icon in the activity

Maybe it should prompt when toggled how many items it will allow one to generate. In non-Edit mode it would decrease that same number down to 0 (and if user saves the story it should keep the decreased number). Probably should show as tooltip the number.

[birbilis]

this mechanism can also be used to pick coloured tiles/boxes (like big pixels) to place on an image

that image could optionally have cells that have tags (to check if correct colors are placed and unlock next StoryPoint) and/or act as magnets to allow snapping to exact place the dropped color boxes

[birbilis]

Most probably the Factory action should occur only when the item is anchored, else it would be hard to interact with the cloned items (they would make more clones by accident). Obviously the clones should be anchored (and maybe should place them with some small offset to the bottom-right (or random) of their (prototype) factory item that serves as a generator button (ideally the factory item should also act upon drag, not just click, to directly drag clones out of it [say if it's an avatar for a player placed at the side of game screen])