Check and evaluate cuelang (base for timoni)

[piontec]

Timoni is based on cuelang. It will be hard to understand timoni without understanding cuelang. We also want to evaluate if we can extend timoni with new features, like schema and doc generation.

### Tasks
- [x] learn cuelang and try it
- [ ] do a knowledge sharing session

[weatherhog]

@piontec is this still needed?

[piontec]

It's a great research topic I never got to do. Let's keep it as a research topic, I'll just remove priorities.