Use localized string representation of numbers

[Pickysaurus]

Improvement

Relates to #1694

Currently

When we show larger numbers in the app, we don't comma-separate them. (e.g. 1000)

We want

To add comma-separation for consistency with the website.

We may need to discuss localisations here, as in some countries they use decimal places instead of commas (1.000 instead of 1,000)

Supporting Information

(Include any supporting screenshots etc to support the above)

Design

(Any designs to required for this feature)

[erri120]

The default integer representation uses the "general format" (G). We probably want N for numbers.

[MattSturgeon]

We may need to discuss localisations here, as in some countries they use decimal places instead of commas (1.000 instead of 1,000)

I know in Java there's a "localized number format(er)" that can use comma, dot, apostrophe, etc as appropriate for the current l10n. Presumably .NET has something similar?