This patch aims for a consistent date display across the entire ui. That it is not always consistent can be seen for example in the event details metadata, where the start date is formatted differently from the created date.

Furthermore, this patch aims to base date formatting more on the chosen locale to create a more intuitive experience for users. No more A.M./P.M. in the german locale for example.

To achieve this, date-fns is chosen as the gold standard and momentjs is removed from the project completely. Not only because moment is legacy, but also because our datepickers were using date-fns already and will not use anything else.

Additionally, this removes our custom date formatting from the translation files and replaces it with date-fns tokens. In my opinion, we do not need to try and be smarter than our datetime library when it comes to formatting dates. Translators retain the ability to enforce their favourite formatting should they so chose,
but will have to be aware that it will not be respect everywhere, e.g. not in the datepickers.

This patch contains changes to all translation files. I am aware that everything except en_US will get overwritten, the changes to other languages are merely for ease of reviewing. If this patch is merged, the translations should be adapted asap as per this example.

Before:

After:

Fixes #1279

How to test this

Can be tested as is. Check anything with dates. Special attention should be payed to the statistics tab and scheduling. Ideally we get people who use other locales apart from the english ones to test this, so they can mention if anything looks very odd in their favourite locale now.