Thruster upgrade modules

Upgrade modules for thrusters are a commonly asked for feature since Keen created the test mod that included them. Upgrade modules would make thrusters more interesting, but a straight up upgrade would be boring and it shouldn't be a flat bonus.

The charge upgrade would increase the force of a thruster for a short amount of time. This would be great for small ships to maneuver and dodge or for large ships to get up to speed and fly without inertial dampeners. Activating the charge upgrade would act as a thruster override for that thruster on max velocity with an increase from the upgrade. After use, the upgrade would have to charge up again before it can be used.

The time upgrade reduces the power/hydrogen use of a thruster the more it's used. When the thruster is not used for a time, the upgrade will become less effective. This is good for lifting thrusters or large ships that accelerate slowly.

The atmosphere upgrade improves the efficiency of thrusters within an atmosphere. It won't increase max thrust of a thruster beyond what the thruster would be capable of performing at its optimal height, but it will make ion thrusters better on low elevations and atmospheric thrusters better on high elevations. There is no effect when used on hydrogen thrusters.