Particle system + 20.3.0.9 support

1. Better support for Skyrim particle system - some "Unknowns" replaced in NiPSysData and BSStripPSysData blocks.
2. Better support for 20.3.0.9 games Divinity 2 and Black Prophecy. Added structure of CSStreamableAssetData found in .item files (actually nif files) of Divinity 2 game.