Localize number formatting

[vsubhuman]

See this comment and following explanation: #2 (comment)

For now - there's en-US locale hardcoded here. We need to try and get current locale from browser to format number for different languages properly.

Might be some complications with cleave used to format numbers in input fields. But I hope it's configurable enough to let me specify order-separator and decimal-separator characters manually. Not sure how user input will be processed then (pressing dot to separate decimal places and pressing local separator key for the same purpose), need to test it out and maybe add some hacks.

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Wiki: https://github.com/antipalos/antipalos.github.io/wiki/Cardano-Calculator:-Localized-number-formatting

[vsubhuman]

@gufmar, watch out for this issue :)

[vsubhuman]

Read detailed description of how this feature now works here: #19 (comment)