Add Arrow-kt support module

[mkotsbak]

It would be nice to have a module with extra support for Arrow library: https://arrow-kt.io/ similar to what Kotest has: https://github.com/kotest/kotest/blob/master/doc/matchers/arrow.md

Here are some of them you are free to add:

/**
 * Asserts the Either value is Either.Right. You can pass in an optional lambda to run additional assertions on the right value
 *
 * ```
 * val name = Either.Right("...")
 * assertThat(name).isRight().hasLength(3)
 * ```
 */
fun <B : Any> Assert<Either<*, B>>.isRight(): Assert<B> = transform { actual ->
    actual.getOrElse { expected("to be right") }
}

/**
 * Asserts the Either value is Either.Left. You can pass in an optional lambda to run additional assertions on the left value
 *
 * ```
 * val name = Either.Left("...")
 * assertThat(name).isLeft().hasLength(3)
 * ```
 */
fun <A : Any> Assert<Either<A, *>>.isLeft(): Assert<A> = transform { actual ->
    actual.swap().getOrElse { expected("to be left") }
}

[evant]

I think this would make sense as a separate lib.

[mkotsbak]

Hmm maybe. It only is useful for people using both of the libraries. At least it should be a separate module in either of the projects to avoid introducing a dependency not all users need.