add option to locate axis labels at positive ends

[corybrunson]

As suggested here, this would communicate important information to the reader more efficiently than reading the tick labels. This should probably be the default option, with other options for the opposite (placing labels at negative ends) and for the current attempt to locate them farther from the action.

I'm having trouble with {reprex}, but the following code produces an example of the current behavior:

library(ordr)
ordinate(USJudgeRatings, princomp) |> 
  ggbiplot() +
  geom_rows_point(elements = "score") +
  geom_cols_axis(aes(label = name)) +
  xlim(c(-5, 8)) + ylim(c(NA, 3.5))