add initiall install asset library button

[BradyAJohnston]

Related to #465, this adds a button in the add-on preferences that the user can click to register the add-on's assets with Blender's asset library browser.

Allows for quicker adding of nodes in GN node trees (through drag-out from sockets) and will allow easier addition of new materials and the like.

• [ ] Potentially add the 'Install Asset Library' as a button for the panels to encourage the user to do so.
• [ ] Ensure proper cleanup of asset libraries on uninstall
• [ ] Categorize nodes for useful categories
• [ ] Rename nodes more generally for human readability