Added variable for modders to make this mod more compatible

Fixed Enhanced Defences tier 5 not being available.

Updated the mod to include tiers 4 and 5 of tiered perks, and also balanced existing perks to be less powerful each tier up but overall more powerful if you have all 5 tiers. This mod should now be slightly less powerful without tiered perks enabled and more within vanilla's value per ascension perk, which still being very useful in fitting the niche that each respective perk addresses.