LibUnicode: Generate per-locale minimum grouping digit values

Previously, we were breaking up digits into groups without regard for
the locale's minimumGroupingDigits value in the CLDR. This value is 1 in
most locales, but is 2 in locales such as pl-PL. What this means is that
in those locales, the group separator should only be inserted if the
thousands group has at least 2 digits. So 1000 is formatted as "1,000"
in en-US, but "1000" in pl-PL. And 10000 is "10,000" in en-US and
"10 000" in pl-PL.

Userland/Libraries/LibUnicode/NumberFormat.h

@@ -15,6 +15,7 @@
 namespace Unicode {
 
 struct NumberGroupings {
+    u8 minimum_grouping_digits { 0 };
     u8 primary_grouping_size { 0 };
     u8 secondary_grouping_size { 0 };
 };