feat: Add open-source license information to welcome modal.

[liam-k]

Closes #117

Reviewer's task:

• [ ] I didn't see no code smells
• [ ] The live preview works as expected -> no regressions found

[render[bot]]

Your Render PR Server URL is https://screenario-pr-120.onrender.com.

Follow its progress at https://dashboard.render.com/static/srv-cd8ifu53t396qjk904u0.