Increase sales tax precision from 2 to 3 decimal places (#1525)

* Allow for tax rates with 3 decimal places

* Update input validation

* Increase precision of create procedure

util/Migrator/DbScripts/2021-08-19_00_FixTaxRate.sql

@@ -0,0 +1,44 @@
+IF OBJECT_ID('[dbo].[TaxRate]') IS NOT NULL
+BEGIN
+    ALTER TABLE 
+        [dbo].[TaxRate]
+    ALTER COLUMN 
+        [Rate] DECIMAL(6,3) NOT NULL;
+END
+
+IF OBJECT_ID('[dbo].[TaxRate_Create]') IS NOT NULL
+BEGIN
+    DROP PROCEDURE [dbo].[TaxRate_Create]
+END
+GO
+
+CREATE PROCEDURE [dbo].[TaxRate_Create]
+    @Id VARCHAR(40) OUTPUT,
+    @Country VARCHAR(50),
+    @State VARCHAR(2),
+    @PostalCode VARCHAR(10),
+    @Rate DECIMAL(6,3),
+    @Active BIT
+AS
+BEGIN
+    SET NOCOUNT ON
+
+    INSERT INTO [dbo].[TaxRate]
+    (
+        [Id],
+        [Country],
+        [State],
+        [PostalCode],
+        [Rate],
+        [Active]
+    )
+    VALUES
+    (
+        @Id,
+        @Country,
+        @State,
+        @PostalCode,
+        @Rate,
+        1
+    )
+END