Document Item Hold Positions

[cosmiccoincidence]

Summary

Document the technical side of the item hold position system.

Goal

Item hold positions are an empty object on item prefabs that indicate the position and rotation of which they should be held by an entity.

Document the system on gitbook under the Systems page and comment the code if needed.

Context

Original PR: https://github.com/RE-SS3D/SS3D/pull/234

Design Doc: https://ss3d.gitbook.io/design/items/hold-positions

[stilnat]

this is already in game, but it needs to be properly set for each item. It's currently not the case for all items in game. I suggest maybe turn that issue into a documentation issue for gitbook, explaining how to make a new item, including setting up custom old positions.

[cosmiccoincidence]

It appears the system only supports 2 attachments points per item currently.

But preferably the should be able to specify a certain amount per prefab which are based on variables... Design doc: https://ss3d.gitbook.io/design/items/hold-positions