replace pre-computed decimals with exact constituent constants

see discussion in pr (#1648 (review))

Author: TS-Andritz

Common/UnitDefinitions/Pressure.json

@@ -421,8 +421,8 @@
     {
       "SingularName": "MilligramForcePerSquareFoot",
       "PluralName": "MilligramsForcePerSquareFoot",
-      "FromUnitToBaseFunc": "{x} * 1.0555790208802639466e-4",
-      "FromBaseToUnitFunc": "{x} / 1.0555790208802639466e-4",
+      "FromUnitToBaseFunc": "{x} * 9.80665e-6 / 9.290304e-2",
+      "FromBaseToUnitFunc": "{x} / 9.80665e-6 * 9.290304e-2",
       "Localization": [
         {
           "Culture": "en-US",