Switch to Luxon

[ajmas]

The project is currently using moment, though it would be good to switch over to using Luxon.

Luxon is essentially the successor to moment, with the moment devs having moved to Luxon. Luxon also has better time zone support.

[ajmas]

Answering myself:

Moment only seems to be used in one location: https://github.com/schej-it/timeful.app/blob/HEAD/frontend/src/components/NewEvent.vue

Looking at Luxon, there doesn't seem to be an equivalent isDST() function at this time, and it would require implementing something custom.