Combat Overhaul 1.9: Armor

Motivation
The Stellaris pre-2.0 armor system is very poorly balanced. Small amounts of armor are utterly useless, while large amounts of armor become very powerful due to the non-linear nature in effective Hitpoints.

Upper limit for Armor was changes to 80% Damage reduction (DR).
This allows us to reduce armor penetration (AP) on weapons a bit. Previously, it was necessary on almost all late game weapons, as 90% armor is just unbeatable without high AP.

Critical point changed to 70% and made more important.
DR per armor point is multiplied by 0.3 after reaching 70% DR. This makes it harder to get to the hard limit.

Armor sources
Armor as a utility has been replaced by hull-hit-point increases. The "0" armor on those is just needed to make sure AI knows how to use them (it's actually ~0.00001). Instead, it is distributed it over two required components. This allows much more control over the values. The non-linear increase in effective HPs is offset by a non-linear increase in armor points. Low level armor (especially on small ships) has pretty high armor values, to make armor useful even on corvettes with only T1 armor tech. Increases in armor with tech, become smaller the higher the tech is. A Dreadnought with max tech armor (both on architecture and hull slot), will have exactly 70% DR. To get to 80%, 5 repeatable techs and "Neutronium ore" or 9 repeatable techs are additionally required.