Revert #11993: new number format system does not and cannot work for CJK languages

There are too many intricacies that I am unaware of that are popping up after
asking whether things are right or not.
I do not want to keep playing whack-a-mole, so just revert the whole thing.

This reverts:
15be383b93
360fe8b0b6
1aa9a5c0ab
59f56941e5
7e2eefb91f
b741b2ba6f
609d0071d5
9f8fd80112
a253205b93
819c6c756e

src/settings_type.h

@@ -222,10 +222,6 @@ struct GUISettings {
 
 	bool   scale_bevels;                     ///< bevels are scaled with GUI scale.
 
-	std::string number_format; ///< formatting string for numbers (like "thousands" grouping)
-	std::string number_abbreviations; ///< mapping to number formats for different powers of ten/thresholds
-	std::string digit_decimal_separator; ///< decimal separator
-
 	/**
 	 * Returns true when the user has sufficient privileges to edit newgrfs on a running game
 	 * @return whether the user has sufficient privileges to edit newgrfs in an existing game
@@ -269,6 +265,9 @@ struct LocaleSettings {
 	byte        units_volume;                     ///< unit system for volume
 	byte        units_force;                      ///< unit system for force
 	byte        units_height;                     ///< unit system for height
+	std::string digit_group_separator;            ///< thousand separator for non-currencies
+	std::string digit_group_separator_currency;   ///< thousand separator for currencies
+	std::string digit_decimal_separator;          ///< decimal separator
 };
 
 /** Settings related to news */