[FEATURE REQUEST] Make Full GUI optional

[abcamiletto]

Hello everyone!

Thanks a lot for this package! It's very convenient.

I am running into a few problems though, and would love to solve them.
The current implementation adds the complete nerfstudio-like GUI to all the examples and downstream use-cases

In my specific case, it breaks my underlying viser app because

• I already have some recording logic in my GUI, I don't need/want nerfview to add its own
• It overrides my GUI theme since it sets dark mode and brand color in the constructor

Is there any chance you can make the GUI optional with a flag in the constructor?

I would love to have only a single button (as shown in the videos in the readme) to toggle it on and off instead of the full nerfstudio GUI