Get plot of fit and forecasted wastewater concentrations

Usage

get_plot_ww_conc(draws, forecast_date, n_draws_to_plot = 100)

draws: A dataframe containing the posterior draws with the data joined to it. This is the draws_df output of a call to wwinference(). It expects the following column names: date, pred_value, draw, and name.
forecast_date: A string indicating the date we made the forecast, for plotting, in ISO8601 format YYYY-MM-DD
n_draws_to_plot: An integer indicating how many draws from the posterior to include in the plot, default is 100

a ggplot object containing faceted plots of the wastewaster concentrations in each site and lab combination