Combat Window Fort level reduction info

[Wiedrock]

The attacking player seems to have 100% accurate info in enemy fort level percentages, when in contact to an enemy. This info should be part of the Combat Window to enable players to see what reduced the fort levels (Art, Pio/Eng, force value/ratio).
Alternatively, the combat log contains an Artillery fort reduction with actual percentages, this could also be added.
The Engineering reduction is also logged to some degree, altough only by giving a general fort reduction at the end of combat.