Feature request - Add social sharing previews to events/<event-slug> pages

**Is your feature request related to a problem? Please describe.**
When users share events on social platforms, it would enhance the Junction brand value if the event links, eg. https://eu.junctionplatform.com/events/junction-2023 , had a preview that can show info about the event and the event logo, as it would allow users to post event links without any extra context needed, as the preview would cover that already

**Describe the solution you'd like**
Add `og:<...>` metatags to /events/ pages

**Additional context**
Currently, the event links have no preview
https://socialsharepreview.com/?url=https://eu.junctionplatform.com/events/junction-2023

Start by locating the entry point for the /events/ pages and inspect how page metadata is currently generated. Compare the rendered head for an event such as junction-2023 with the social preview requirements; done means the event link exposes OG metadata containing the requested event information and logo, and the preview displays it correctly.

索引モデルが issue の本文から書いたものです。