Temporarily create new year pop data

[mcuadera]

Closes #290

This fix creates new population data using the latest growth rates available. To test the function, run in the Sandbox:

apply_growth_rate_to_pop_data(
pop_dir = "GID/PEB/SIR/Sandbox/data/pop",
ctry_pop_path = file.path(pop_dir, "ctry.pop.long"),
prov_pop_path = file.path(pop_dir, "prov.pop.long"),
dist_pop_path = file.path(pop_dir, "dist.pop.long"),
growth_path = "GID/PEB/SIR/Data/pop/pop raw/WPP2024_GEN_F01_DEMOGRAPHIC_INDICATORS_COMPACT.xlsx"),
                                          edav = TRUE
)

It will create three parquet files with -unofficial suffixes. Because these are estimates using growth rates, and the 2026 population counts are not coming from WHO, these are "unofficial" numbers. Once we receive the new population counts, we will have to recreate our population data with those new estimates instead of relying on this function.

The apply_growth_rate_to_pop_data() will most likely be only used rarely and bridges the information gap between when new pop estimates are reported. In addition, we must also check for a new growth rate file, if there's one available. Details on where this growth rate file is located is in the function description.