New exercise teaching alternative number types

This is part of our September Spring to get the Go Track in shape. Please read the [Overview issue](https://github.com/exercism/go/issues/1610) for more details. **This exercise is unclaimed. To claim it, please comment below.**

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**Before building this exercise (or exercises), please read up on [the documentation](https://exercism.org/docs/building/tracks/concept-exercises).**

Cars Assemble teaches `int` and `float64`. We need an extra exercise to teach the other number types that are commonly used and returned in Go. This can go into greater detail on more advanced numerical concepts.

It is also entirely possible to create _two_ exercises: one on integral numbers, and one on floating-point numbers. This is the approach taken by C#, see the https://github.com/exercism/csharp/tree/main/exercises/concept/interest-is-interesting and https://github.com/exercism/csharp/tree/main/exercises/concept/hyper-optimized-telemetry exercises.