Add Sessionize conference theme

[lukket]

After you have read the instructions for adding a theme, please make sure:

• your theme.toml is complete
  • name
  • license
  • licenselink
  • description
  • homepage
  • demosite (if one exists)
  • tags
  • features
  • authors/author (depending on whether the theme has multiple or a single author)
  • original (if the theme is a fork)
• you're using absolute paths for images in your README
• you've got appropriate thumbnail and screenshot images
• your theme comes with an appropriate license

[netlify]

✅ Deploy Preview for hugothemes ready!

Name	Link
🔨 Latest commit	80dc5de
🔍 Latest deploy log	https://app.netlify.com/sites/hugothemes/deploys/679234e1feb31c0008f2844e
😎 Deploy Preview	https://deploy-preview-519--hugothemes.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[hugo-sid]

@lukket, thanks for adding Sessionize conference theme.