Peery 9b91d2c8a9 Missile Side Thrusters and new Shader path
Changed the missile model to also include thrusters for rotational purposes and gave them the same exhaust shader.
Each shader is a unique instance and displayed thrusts can be set with set_X_rotational_thrust(), set_Y_rotational_thrust() and set_main_engine_thrust() in the missile root respectively.

Also added a second missile in the space scene just for debugging purposes.
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entities Missile Side Thrusters and new Shader path
environment/skyboxes/nebula_space Added Asset Space Nebula Skybox