Implement new Concept Exercise: Type Parameters (aka Generics)

In February 2022 Go 1.18 will land and include generics. I am sure students would love it if we could provide a concept exercise on that soon after the release. This is dummy issue for now in case someone wants to volunteer for preparing such an exercise.

The new features might also require more than one exercise. If someone has a good idea how to split things up, we could do that.

## Getting Started

If you have not yet contributed to concept exercises before, this task requires some upfront reading to acquire the necessary background knowledge.

Here you can read about what Concept Exercises are and how they are structured:

- [What are Concept Exercises?](https://exercism.org/docs/building/product/concept-exercises)
- [Concept Exercises](https://exercism.org/docs/building/tracks/concept-exercises)
- [Concepts](https://exercism.org/docs/building/tracks/concepts)

Also be aware of these general guidelines.

- [Exercism Markdown Specification](https://exercism.org/docs/building/markdown/markdown)
- [Exercism Formatting and Style Guide](https://exercism.org/docs/building/markdown/style-guide)