Feature request: number localization

[IvanSanchez]

This is a follow-up of #70/#78, re: numbers of credits in trade goods tables.

I use the ES-es locale, which means that "ten thousand" is written as 10.000 with a dot as the thousands separator. I find it slightly irritating to see numbers pre-formatted in the EN-us locale, such as as 10,000.

I'm specifically thinking of leveraging https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toLocaleString - then wrap each number in a <span> CSS class and perform a bit of magic with document.querySelectorAll. Maybe throw in some data attributes to keep track of units of measurement per <span>.

Bonus super fancy request: see if there's a way to leverage currency formatting (since some locales put the currency symbol as a prefix instead of as a suffix) while using imperial credits/kilocredits (Cr/kCr) as the currency symbol.

This might arguably need a whole new "settings" section on the site, to let users override the browser's default locale and set a cookie to do so.

[Grauenwolf]

We're going to need the concept of "user settings", probably stored in a cookie because we don't have a database.

Also need to research user local/culture settings in Blazor. Unfortunately the JavaScript library isn't going to work.