Arena progression

[tukkek]

Giving reputation bonuses for each Arena Fight would solve some of the issues with Arena-only playthroughs, such as not being able to recruit units.

Acquiring items is also not ideal, as players are dependent on caravans which are not very common in the early game. An "assemble caravan" Treaty could be added and Arena reputation being doubled to account for generating both hires and caravans when those become available (perhaps once per season each)?