choose year of reference in report_mig_interannual

This is already implemented in summary, with a nice box ribbon to select the year, do that for all the plots (in stacoshiny later) First though we need to modify the plot method Currenltly the choice of selected year is interactive....

	if (silent == FALSE) {
	the_choice <-
	as.numeric(
	select.list(
		choices = 
                     as.character(unique(dat$bjo_annee)[order(unique(dat$bjo_annee))]),
		preselect = 
                           as.character(max(dat$bjo_annee)),
		"choice annee",
			multiple = FALSE
					)
				)

pass it as an argument (selected_year) of the function + unit_test it