Add website analytics consent

[akadlec]

Summary

• Replaces the always-on Umami script in the website layout with a consent-managed analytics component.
• Loads the new Studio81 analytics script only after the visitor accepts optional analytics.
• Adds a compact accept/decline EU cookie consent banner with storage-blocking guards.

Validation

• pnpm --filter @fastybird/smart-panel-website run build
• git diff --check
• Browser check against the static export confirmed the banner appears, analytics is absent before consent, and accepting injects https://analytics.studio81.cz/script.js with the requested website ID.