Add a tax rate system to the tech tree, adds an additional scrap cost to each purchase on the tech tree Tax rate is assigned by workbench level, defaults are: Tier 1 = 0% tax Tier 2 = 10% tax Tier 3 = 20% tax Tax rates are configurable via server.workbench1TaxRate, etc (clamped between 0 and 100%) Tax rates are displayed on the purchase button on the tech tree This tax is exclusive to the workbench, research table costs are unchanged Moved ScrapForResearch from ResearchTable.cs to Workbench.cs as it was only used for work benches