Invest consumables

[dogancana]

There should be an investment method similar to invest low players, but instead for consumables.

Trade logic: Invest methods in general depends on wrong valuation of items. In this feature we can have a predefined list of consumable id to price map and search market for 20% profit margin.
Consumables are generally sold/bought with buy now prices. That's why this feature's implementation should be pretty similar to low player investment.