i18n for dates

[Lanny]

Currently we always use English formatting for dates, but we support multiple UI languages and should respect language differences in date formatting. E.g. "January" should be "Januar" here:

date-fns which we use in our formatLongDate and formatShortDate seem like they take a locale option so this should be pretty simple.

[robin-macpherson]

Ooh good find re: the locale option with date-fns! Maybe this will make our lives easier also with our relative time stamps 😄

[La-Catalaneta]

Hi Lanny and Robin.

Just a note that the screenshot date is actually the American format only and it's not used in the UK, nor Australia and New Zealand. British English format should be "7 January, 2021". more info.

This brings the issue that I previously commented when translating the UI into Catalan where European Spanish and British English would benefit massively of being separated from Latin Spanish and American English as some words may sound really weird across the pond, and date formats also differ on both sides.