build_grouped_irrs: Create rollup of IRR based off of dates
In AZASRS/AZASRS: ASRS Database R API

Build IRR for any rollup and date range, including ITD and cash adjusted

build_grouped_irrs(
  start_date,
  end_date,
  itd,
  cash_adjusted,
  nav_daily,
  cf_daily,
  pm_fund_info,
  ...
)

`start_date`	is the start date of analysis
`end_date`	is the cutoff date of analysis
`itd`	is a boolean that determines whether itd (inception to date) is included
`cash_adjusted`	is a boolean that determines whether cash is adjusted
`nav_daily`	is the object of get_pm_nav_daily()
`cf_daily`	is the object of get_pm_cash_flow_daily()
`pm_fund_info`	is the object of get_pm_fund_info()
`...`	aggregation choices from from pm_fund_info (i.e. pm_fund_portfolio, pm_fund_category, pm_fund_id)
`.data`	is from clean_nav_cf()

# Example use case
nav <- get_pm_nav_daily() %>% dplyr::filter(nav != 0)
cf <- get_pm_cash_flow_daily() %>% dplyr::filter(cash_flow != 0)
pm_fund_info <- get_pm_fund_info()
start_date <- "2019-09-30"
end_date <- "2019-12-31"
itd <- FALSE
cash_adjusted <- FALSE
final_data <- build_grouped_irrs(
  start_date = start_date, end_date = end_date, itd = itd,
  cash_adjusted = cash_adjusted, pm_fund_info = pm_fund_info,
  pm_fund_portfolio, pm_fund_category_description
)