Removing the old links and setting back to the demo

[travjenkins]

Also preparing for this to open the banner again when things change

Changes

• Remove Feb 10 webinar link
• Add back in link to Demo
• Add support for the banner to open when a new webinar is added

Tests / Screenshots

• Manually hit the home page. Nothing shows because I had dismissed it and we still use the old key to check if the user has dismissed already

• Altered the value to cause the demo to show up

• Added a fake webinar

[github-actions[bot]]

Visit the preview URL for this PR (updated for commit 0afe4c4):

https://estuary-marketing--pr248-travjenkins-webinar-tchw6j4a.web.app

_{(expires Sat, 11 May 2024 20:47:02 GMT)}

_{🔥 via Firebase Hosting GitHub Action 🌎}

_{Sign: 76f6b095a0752e5d9c6c890267f9fdc3e392161e}