[suggestion] Track iCal link should trigger webcal subscribe, not download

[saerdnaer]

On a Track detail page like https://fosdem.org/2026/schedule/track/dev-random/ the link iCal should point to webcal://fosdem.org/2026/schedule/track/dev-random.ics instead of https://fosdem.org/2026/schedule/track/dev-random.ics – which would trigger a subscription to that ical feed instead of downloading the schedule state at this time, which gets obsolete quite fast.