We shouldn't be dragging both codes and actual names of tibble columns all the time but rather only work with codes, which is less error prone and more efficient. This PR adds some helper functions to add the equivalent column in a given tibble, e.g., add_area_name adds a name column to a tibble that already contains a code column, and add_area_code adds a code column to a tibble that already contains a name column.

I also became aware of Tidyverse recommendation for dealing with tidy selection R CMD Check notes, which is not how we are doing it (we are currently ignoring warnings using utils::globalVariables). In the next PR I will try to:

• Fix this not recommended usage. Start using the approach given in the link above.
• Remove natural name columns from all our data, only work with codes, and leave names for debugging/visualization by using the provided utils functions.