support st_read() in open_dataset()

[cboettig]

url <- 
 paste0("https://github.com/cboettig/duckdbfs/raw/25744032021cc2b9bbc560f95b77b3eb088c9abb/inst/extdata/",
 "world.gpkg")

# read from a geopackage file over https:
countries <-  paste0("/vsicurl/", url) |> open_dataset(format="sf")

# perform spatial ops outside of R / outside of RAM
library(sf)
melbourne <- st_point(c(144.9633, -37.814)) |> st_as_text()
countries |> 
  filter(st_contains(geom, ST_GeomFromText({melbourne})))  

# and read in:
sf_obj <- countries |> filter(continent == "Africa") |> to_sf()