Irrigation statistics: the `summary` method for `CW_output` object

#' Statistics on applied irrigation
#'
#' This function produces annual statistics on applied irrigation from simulation result.
#' 
#' @param cw_output CropWat simulation result (See CW_run_simulation)
#' @param probs numeric vector of probabilities with values in [0,1]
#' @param ... Other parameters passed to [quantile]
#'
#' @return A [data.frame] with one row by year and the following columns:
#' - `year`
#' - `sum`
#' - `nb_days`: number of days of irrigation
#' - `mean_day`: average value of irrigation dose per irrigation day
#' - `Qxx`: one column by quantile of daily applied irrigation
summary.CW_output <- function(object, probs = seq(0, 1, 0.25), ...) {
}