Combine dynamic and static polar plotting functions

[jack-davison]

This PR closes #59, but evolved considerably from it.

In short, it deprecates polarMapStatic() in favour of a static = TRUE argument on polarMap().

There are a few (I think) good reasons for doing this:

• Easy toggling between dynamic and static maps.
• Consistent API for users.
• Less scope for oversights/bugs
• Alignment with the design of {openair}, which arguably prefers fewer functions with more arguments over more functions with fewer arguments.

The evolution of this has extended to:

• A significant refinement of function documentation.
• Consistency of the use of type across nearly all functions (e.g., trajMap()).
• Ensuring type is always passed to openair::cutData() (was not in trajMapStatic()).
• Simplification of buildPopup()

devtools::load_all()
#> ℹ Loading openairmaps

polarMap(polar_data, pollutant = "pm10", static = TRUE)
#> ℹ Assuming latitude is 'lat'
#> ℹ Assuming longitude is 'lon'
#> Warning in st_point_on_surface.sfc(sf::st_zm(x)): st_point_on_surface may not
#> give correct results for longitude/latitude data
#> Loading required namespace: raster

^{Created on 2024-04-15 with reprex v2.0.2}