Update front facing videos

[hidmic]

Proposed changes

Precisely what the title says. This patch updates both the repository README and the documentation index page to show a slightly more enticing video of Beluga in action.

Type of change

• 🐛 Bugfix (change which fixes an issue)
• 🚀 Feature (change which adds functionality)
• 📚 Documentation (change which fixes or extends documentation)

Checklist

• Lint and unit tests (if any) pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)
• All commits have been signed for DCO

[nahueespinosa]

LGTM!

[hidmic]

Skipping CI as this does not affect code.