Add PyCon KR 2023 videos

[jungmir]

Add PyCon KR 2023 videos.

HelloPy members are updating PyConKR 2023 Videos.

[jonafato]

Thank you! A couple of requests:

• Can you remove the conference name and speaker names from talk titles? PyVideo has dedicated fields for conference name and speaker name, and this change will make talk titles on pyvideo.org match the titles used on the conference's official talk list at https://2023.pycon.kr/session.
• Can you update the JSON file names to be lower-case and replace with -? My usual tool for this task is python-slugify to generate the filename with slugify.slugify(talk_title) + ".json".

[jungmir]

Thanks for the feedback, I've included everything you requested for.

[jonafato]

Thank you for the updates! I'm going to push a couple of minor changes to your branch to improve the rendering on the site and then merge this PR.