FixedView Camera but with settable position and orientation.

[joelsa]

Hi, and thank you for your crate.

I'd really like the FixedView camera and I use to visualize some things in 3D, where I don't want the users to be able to move or zoom.

However, it is quite tedious to transform everything so it it is the frame with camera looking in negative z-direction.

It would be great to have a similar camera, but with a settable position and orientation.

It is straightforward to build this, and I am willing to implement this, however before putting in a PR I'd like to ask if this is a feature that has chances at getting merged?