12 calculate match success rate

[jacobvjk]

closes #12

• workflow.multi.loanbook gains script run_calculate_match_success_rate.R, which calculates the match success rates in terms of...
  • matched number of loans and matched loan size
  • both in absolute and relative terms
  • for individual loan books and the meta loan book
  • and produces plots using plot_match_success_rate()
• gains plots.R which contains the relevant plotting function
• gains additional parameters documented in example.config.yml that allow adjusting the output format of the plots
• updates object names in expected_columns.R to better match their usage and updates the relevant scripts accordingly (this could have been a separate issue but given the change is very small I opted to include it here)

NOTE: plot_match_success_rate() should be moved to pacta.multi.loanbook.plot or r2dii.plot at some point and exported (see RMI-PACTA/r2dii.plot#563)

[jdhoffa]

lgtm!

[MonikaFu]

Sounds like something that should live in r2dii.plot since it is relevant also for non-multi users, right? Happy to work on it when I get a mandate.