[WIP] Display plenary talks on event page

[davidstap]

Note: this is very much a work in progress!

Summary

This pull request aims to display plenary talks (e.g., these from ACL 2022) on the relevant event pages. Currently, some plenary talks are stored in data/xml but are not displayed on the website.

Display strategy

The exact method for displaying these talks is still under consideration. One option is to list the talks below the existing Website and Handbook links on the event page (see e.g., ACL 2022). Another option is to link to a dedicated page where all talks are collected.

Additionally, each talk should have a dedicated landing page, similar to how papers are presented, including the ability to cite the talk.

Rough roadmap

• [x] Store talks in class EventIndex when available.
• [ ] Store talks in Hugo data folders when running bin/create_hugo_yaml.py.
• [ ] create a Hugo layout for talks in hugo/layouts/talks.
• [ ] Ensure talks are generated during website build (modify bin/create_hugo_pages.py)
• [ ] Add all available talks that are stored on the server (currently only 2022.acl.xml includes talks)