IComparable for complex params

[mrahhal]

All the types in PrimitiveComparer are actually already IComparable, so I feel we can just remove this whole part altogether and have a single implementation that uses IComparable. Thoughts?

Not sure if just removing it will replicate current behavior, since it does some stuff with enums, and it also even does a string comparison (which feels weird to me since there's already a string comparison in ParameterComparer.Compare).

Closes #2301

[adamsitnik]

Overall it LGTM, I just left one suggestion for improvement.

@mrahhal thank you for your contribution!

[AndreyAkinshin]

It looks great, thanks! The only suggestion I have is about the intro example. We are trying to keep them as small as possible. I would suggest removing non-essential comments (e.g., "property with public setter", "public property") and simplifying some of the methods. E.g., instead

public int CompareTo(ComplexParam other)
{
    if (other == null)
    {
        return 1;
    }

    return Value.CompareTo(other.Value);
}

we can write

public int CompareTo(ComplexParam other) => other == null ? 1 : Value.CompareTo(other.Value);

[AndreyAkinshin]

@mrahhal could you please also rewrite IntroComparableComplexParam.CompareTo(object obj)? Currently, it occupies too much space in the sample (while this particular implementation is not so important).

[mrahhal]

Sure. Simplified it as much as I can.

[AndreyAkinshin]

LGTM

[AndreyAkinshin]

@mrahhal thanks for your contribution!