ENH: Add CompletableFuture asByteArray(), asLines() asInputStream()

[rbygrave]

  /**
   * Process as response {@literal HttpResponse<byte[]>}.
   *
   * @return The CompletableFuture of the response
   */
  CompletableFuture<HttpResponse<byte[]>> asByteArray();

  /**
   * Process as response {@literal HttpResponse<Stream<String>>}.
   *
   * @return The CompletableFuture of the response
   */
  CompletableFuture<HttpResponse<Stream<String>>> asLines();

  /**
   * Process as response {@literal HttpResponse<InputStream>}.
   *
   * @return The CompletableFuture of the response
   */
  CompletableFuture<HttpResponse<InputStream>> asInputStream();