merge_nav_and_cf: Merge NAV and CF
In AZASRS/AZASRS: ASRS Database R API

Merging both NAV and CF and handle complexity of rollup aggregation

1	merge_nav_and_cf(.nav_data, .cf_data, end_date, cash_adjusted, pm_fund_info)

`.nav_data`	is from get_pm_nav_daily() through convert_start_date to negative()
`.cf_data`	is from get_pm_cash_flow_daily() through filter_cf_between_dates
`end_date`	is a string (format yyyy-dd-mm)
`cash_adjusted`	is TRUE / FALSE to allow for cash adjusted NAV at next quarter
`pm_fund_info`	from get_pm_fund_info()