Feature request: Add usage + cost info to sprite cli and api

[khalido]

As the title says. Two requests really:

1. Add a cpu usage + cost columns to the table outputted bysprite list (and adds a total bar below the list).
2. a usage API endpoint which includes a cost field.

• add a cpu usage and cost field to GET and LIST sprites exisiting API endpoints

Why: It would be nice to know how much running a sprite is costing.