Create a redirect link for individual events with proper OpenGraph

[j-hariharan]

The goal is to send a link, currently /events#event_id along with the spam for each event. This works currently by simply opening the modal for the correct event on the events page. But since the event_id is in the "hash" part of the URL, it is not accessible in the generateMetadata() function in NextJS which is responsible for adding openGraph metadata to the link, leading to good display in WhatsApp messages. This has been used in the blogs pages.

Since we cannot currently achieve this for events, we would like to make a separate /events/event-slug (using slug for all the same reasons as #47) page which exports a good OpenGraph and immediately redirects to the existing /events#event_id link.