consider integrating plot_match_success_rate() from pacta.multi.loanbook

[cjyetman]

The plot_match_success_rate() from pacta.multi.loanbook has/had a TODO comment to move plot_match_success_rate() here to r2dii.plot and export it. The comment will be removed, but the concept is now being tracked here.

https://github.com/RMI-PACTA/pacta.multi.loanbook/blob/03d3c10346d3c0a0bb132cb225a3cce01bfb307b/R/plots.R#L1-L6

# TODO: move to `r2dii.plot` and export
plot_match_success_rate <- function(data,
                                    metric_type = c("absolute", "relative"),
                                    match_success_type = c("n", "outstanding", "credit_limit"),
                                    currency,
                                    by_group) {

• related deal with moving plot_match_success_rate() into r2dii.plot TODO pacta.multi.loanbook#236
• related upkeep: Review and remove all TODO, FIXME, and any other comments used to kick cans down roads pacta.multi.loanbook#213

[cjyetman]

This seems to be a duplicate of #563