Support more scene-item commands

[ellnix]

Wanted to try specifically set_transform, but could add whole set of commands that obws supports: https://github.com/dnaka91/obws/blob/969afb3f02d494291334cb838cd3003fb155aa25/src/requests/scene_items.rs#L11

I would be willing to make a PR for this, if there's interest :smile:

P. S.: The --help command should really list the scene-item commands that are supported, but that's another issue.

[grigio]

Sure, you can propose a PR