examples: add more .obj files for 06_obj_viewer

[spytheman]

I had these in my Downloads folder, but I could not find where I got them, and they do not seem to have sources mentioned in them 🤔 .

They look like this:

[spytheman]

I think that the utahTeapot.obj is common enough to be included without problems, it even has its own wiki article: https://en.wikipedia.org/wiki/Utah_teapot .
Same with the cubes and the floor .obj files.

The plane.obj, stall.obj and objtext.obj are murkier, since I do not know their sources and license.

[spytheman]

donut.obj does not look good, but it was made within 5 minutes with Blender by me, so it should be safe to use.

[larpon]

The donut looks more like an onion ring 😄

[spytheman]

The donut looks more like an onion ring 😄

Yeah, I am a very lousy cook, that does not know how to use blenders and stuff 😄.

[spytheman]

The donut looks more like an onion ring 😄

Yeah, I am a very lousy cook, that does not know how to use blenders and stuff 😄.

I should have hired a chef 🤔 .