NHSD colour scales

[mirober]

Adds a couple of utilities for creating consistently coloured GG plot graphs, with most colours taken from here.

The main ones are scale_colour_nhsd and scale_fill_nhs, example usage:

library(gapminder)
library(tidyverse)

countries <- c("United Kingdom", "China", "Gambia")

gapminder %>%
  filter(country %in% countries) %>%
  ggplot(aes(year, lifeExp, colour=country)) +
  geom_smooth(se = FALSE) +
  labs(
    title = "Life expectancy",
    x = "Year",
    y = "Expectancy",
    caption = "Source: gapminder (2020)"
    ) +
  theme_minimal() +
  scale_colour_nhsd("blue") +
  ggsave("test.png",
         type = "cairo",
         width = 7,
         height = 4,
  )

[murd0]

Thanks for being the first contributor, Mike!