Add resultflow module

[osipxd]

No description provided.

[osipxd]

Q: Should we also provide an extension Flow<T>.onEachState(...)?
A: I don't think so, as it could lead to puzzles like this:

resultFlow { repository.fetchData() } // Flow<Result<T>>
    .foldEach(
        onSuccess = ::handleResult,
        onFailure = ::handleError,
    ) // Flow<R>, often Flow<Unit>
    .onEachState { resultState ->
        // Will never be printed as the failure was already handled earlier
        if (resultState.isFailure) println("Error")
    }

[AleksandrTabolin]

@osipxd aproove