added Advanced_Pricing_Calculator spreadsheet tool

tools/AdvancedPricingCalculator/Advanced_Pricing_Calculator_README.md

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+## mod-ah-bot Advanced Pricing Calculator
+This spreadsheet helps show the buy and sell prices that the Bot(s) will use based on your configuration when `AuctionHouseBot.AdvancedPricing.<Category>.<Subclass>.Enabled` is `true` .  
+
+### How to Use
+**Edit only the “Config” tab**
+   - This tab contains many adjustable settings from the module’s config file
+   - Change these values to match your server’s setup
+   - Items in other tabs reference the `Config` tab, so values will update immediately
+
+<br>
+
+**You shouldn’t need to modify anything outside the Config sheet unless you know what you're doing.**  
+*There are hidden columns in each tab that can show items' Quality, Vendor Price, and Item Level (according to the database).  
+If you make custom changes to your database info, consider updating these as well for accurate pricing.*
+
+### Notes
+- The spreadsheet does not consider the following settings:  
+    - AuctionHouseBot.Buyer.AcceptablePriceModifier  
+    - AuctionHouseBot.BidVariationHighReducePercent  
+    - AuctionHouseBot.BidVariationLowReducePercent  
+    - AuctionHouseBot.BuyoutBelowVendorVariationAddPercentEnabled  
+    - AuctionHouseBot.BuyoutBelowVendorVariationAddPercent