reworked tribe mechanics
a couple new uncivilized governments :3
some of this is vanilla behavior (you can change what a tribe will turn into after civilizing by changing its CAN_BECOME_CIVILIZED attribute), but i added a bit more to it,,
tribes that civilize into certain ideologies (in this case, monarchy and republic) will have a 20% chance to turn into another random ideology (other than rebels and other tribes)
additionally, tribes will ALWAYS colonize 2 provinces after civilizing, which imho is a big improvement from vanilla behavior (randomly picking a nearby province - including sea and your own provinces - and attempt to capture it)
as a last little change, i removed tribes' ability to capture neutral provinces using an army (cuz i thought it was a bit silly, very abusable by the player, and colonization is way better now anyways.