Base: refactor unit formatting defaults

Defaults for both precision (number of digits after decimal point)
and denominator (number of fractions) are defined on various places
making difficult to find which default is used for various tasks.
Store these values at one central place: UnitsApi. Unless overriden
by user, default values are defined by unitSchemasDataPack.

src/Base/Quantity.cpp

@@ -57,23 +57,18 @@ using Base::Quantity;
 using Base::QuantityFormat;
 using Base::UnitsSchema;
 
-// ====== Static attributes =========================
-// NOLINTNEXTLINE
-int QuantityFormat::defaultDenominator = 8;  // for 1/8"
-
-
 QuantityFormat::QuantityFormat()
     : option(OmitGroupSeparator | RejectGroupSeparator)
     , format(Fixed)
-    , precision(static_cast<int>(UnitsApi::getDecimals()))
-    , denominator(defaultDenominator)
+    , precision(UnitsApi::getDecimals())
+    , denominator(UnitsApi::getDenominator())
 {}
 
 QuantityFormat::QuantityFormat(QuantityFormat::NumberFormat format, int decimals)
     : option(OmitGroupSeparator | RejectGroupSeparator)
     , format(format)
     , precision(decimals < 0 ? UnitsApi::getDecimals() : decimals)
-    , denominator(defaultDenominator)
+    , denominator(UnitsApi::getDenominator())
 {}
 
 // ----------------------------------------------------------------------------