Reduce shield stacking penalty

I suggest changing stack_effectiveness of shield to 0.95

The stacking penalty for shield is too great. At the current 0.9 stacking penalty

1, 0.9, 0.81, 0.729, and 0.6561

The marginal utility will be

100%, 80%, 63%, 48.6%, and 36.55%

That’s too much of a penalty for anyone to use more than 2, and that’s exactly what we get, 0 - 2 shields on every ship.

I’ve noticed the very same phenomenon. The existing stack rule makes for boring, predictable loadouts as well as needlessly prohibiting the option to pursue a costly but superior shielding loadout. I support the suggested change.