Added rational number fuzzer functions and corresponding tests

[adrian052]

Functions Added:

1. rational: Generates a random rational value within the range of [-255; 16383].
2. rational_between: Generates rational values between specified bounds.
3. rational_at_least: Generates a random rational value with a lower bound constraint.
4. rational_at_most: Generates a random rational value with an upper bound constraint.

Note:
The current range for rational_between is set between -255 and 255. However, this range is flexible and could be adjusted based on any further requirements or suggestions.

[KtorZ]

Sorry, I started reviewing this a while back but never posted the pending review 🤦.

I've pushed some minor style adjustments, but I haven't reviewed the code in depth. Two things caught my attention so far:

• The distribution for rational and rational_between are somewhat odd.
• It's unclear to me at this point why rationale bounds are limited to -255 -> 255 🤔