Remove momentjs in favor of an actively maintained date library

[TimDaub]

• Working with dates in JS is a PITA
• moment was a good choice to work with dates in js, but has officially become deprecated: https://momentjs.com/docs/#/-project-status/
• The moment project maintainers, in their blog post, make recommendations for other date libaries.
• One that I can personally recommend in that list is date-fns https://date-fns.org/
  • It's great because each function is standalone and hence only a small subset of the whole API is actually imported into the runtime when using the library
  • In the frontend this has the benefit of being able to apply treeshaking
  • In the backend, like is the case here, I'd argue that date-fns's approach limits the risk of getting exposed to an npm supply chain attack

Anyways, key point here is that an actively maintained date library should be preferred.