Make 'gdal pipeline' support mixed raster/vector pipelines

[rouault]

e.g:

$ gdal pipeline read points.csv ! grid average ! write out.tif
$ gdal pipeline read poly.shp ! rasterize --outsize 256,256 ! write out.tif
$ gdal pipeline read in.tif ! footprint ! buffer 20 ! write out.gpkg

"Ported": grid, rasterize and footprint Still remaining to "port": polygonize and contour

Fixes #12557