[feature] keyboard input

[koebel]

From a usability perspective, it would be nice if the extension would support keyboard input. I think some of the most common keyboard commands for 3D object manipulation are

• WASD are most commonly used in computer games for moving one's avatar
• also game engines like Unity 3D use WASD to move the camera left/right/forward/backward and Q and E keys to move it up and down
• +/- as well as arrow keys are also often used for changing zoom and moving objects

User Story

As a user
I want to manipulate the position and scale factor of my 3D object using the keyboard
so that I can preview the files without using mouse input.

Acceptance Criteria

• support of keyboard input

[koebel]

also properly implement exit using "esc" key, see #10 (comment)