Add support for i18n in number formats

[samreid]

In https://github.com/phetsims/special-ops/issues/275#issuecomment-2529442327 @kathy-phet said:

If you think its a reasonable idea, another intern project would be to support different number formats in our common code - working towards locale support for that...

Different languages use spaces, commas, dots, like so:

Locale	Numeric Format	Percent Format
en-US	1,234,567.89	50.00%
fr-FR	1 234 567,89	50,00 %
de-DE	1.234.567,89	50,00 %
sv-SE	1 234 567,89	50,00 %