Creating a polygon for an MPU using SHIP_NODE_REGISTER.gd

A short demonstration for modifying the polygon of an MPU added through SHIP_NODE_REGISTER.gd. This is purely using a temporary ship scene to collect the raw data stored, and add it to the property for the driver entry, with it being set to process using the `arr2vec2arr` method to convert it into a PoolVector2Array before being used as it's polygon.