Migrate from `moment` to `date-fns`

[Rotzbua]

Changes

• Use Unicode Tokens https://github.com/date-fns/date-fns/blob/main/docs/unicodeTokens.md
• Create date functions helper
• Use date-fns for chart.js

Bugs

• Chart tooltip shows time, should be solved later in the chart.js upgrade

Reference

First part of the solution for #621

[gustav87]

The MMR/RP data is on the wrong dates on the player MMR timeline chart because of the UTC conversion to local timezone. Is that fixed when we use a newer version of chartjs, or could we address it now?

[Rotzbua]

should be solved with https://github.com/w3champions/website/pull/628/commits/b93f29a984d4597697b64c291375e654faf40699

edit: reordered and rebased into this pr

[gustav87]

For some reason, chartjs still puts the wrong dates on the x-axis. The data is on the correct dates now, though, so that's good.

[Rotzbua]

Thanks for pointing out the problem 👍

For some reason, chartjs still puts the wrong dates on the x-axis

Unfortunately the x-axis is right. The chart starts with Jan 24, 2023, 11:44pm but is not labeled because the next tick is just 16 minutes later and for readability reasons the first x-axis-label is Jan 25. 🔍

Of course that is not the intended behavour. The reason is that before only a string with the date was provided. Now a Date object is used. To get the same result the Date has to be set to the start of the day.

[gustav87]

Awesome work, man. Merging!