Adapt EuroPython bot to PyLadiesCon

[cmaureir]

Closes #2

[egeakman]

All looks good to merge! Thank you @cmaureir! We can implement the URL per session logic after all the videos and their URLs are ready!

[marcorichetta]

• I found an error thanks to the tests, which led me to adding a default for the youtube_url field.
• I also had to enable the CI workflows from the Actions tab. They're not ran by default in a forked repo.

[egeakman]

Thanks for the additions @marcorichetta!