Implement cost models

[fabianishere]

A large factor in real-world decision-making is, naturally, the financial picture. Buying/leasing servers comes with certain costs, just as power supply does. The former can even be interpolated to compute the per-hour cost of a certain resource, to accurately be able to quantify the cost of running certain workloads or introducing certain resources to the mix. Adding client-side cost models (how much customers are charged) would make this even more realistic, but this also adds a significant amount of complexity. SLA penalty calculations could also be added for more realism, using the available failure models.

This includes:

• Similarly to how power consumption is be modeled, each rack and machine should not only compute the power it uses, but also its cost of ownership. For this, the cost of each resource type needs to be recorded
• For each unit of power consumption, a cost needs to be accumulated
• Nice to have: implementing client-side models
• Nice to have: implementing SLA penalties