Feature: add spawning cost tables to API

[L0laapk3]

It would be nice to have these costs in the API such that they don't have to be hardcoded into every bot. Especially because they are prone to changes for balancing. current_spirit_cost exists but it is not enough.

I propose that you add 2 arrays to every Base object: (example for circles)

base.spawn_cost_tresholds = [50, 100, 200];
base.spawn_cost_values = [25, 50, 90, 150];

[L0laapk3]

Same goes for outposts :)

outpost.damage_multiplier_tresholds = [500];
outpost.damage_multiplier_values = [1, 4];