add vrt_dsn column and use warper for all read

[mdsumner]

altimetry_antarctica_daily_files
amps_d1_icefiles
amps_d1files
amps_d2files
amps_model_files
ccmp_files
chla_johnsonfiles
chlafiles
cpolarfiles
cpolarfiles_old
currentsfiles
derivaadcfiles
derivicefiles
fasticefiles
ghrsstfiles
icefiles
nsidc_north_monthly_files
nsidc_south_monthly_files
oc_sochla_files
ocfiles
rapid_responsefiles
salfiles
sshfiles
sstfiles
windfiles

[mdsumner]

here is an example of the new read scheme

 files <- sstfiles()
## these are fully expanded VRT chunks (but with GDAL 3.7 we'll replace with vrt:// syntax)
f <- files$vrt_dsn[1:10]
a <- lapply(f, vapour:::gdal_raster_data, target_ext  = c(100, 220, -60, -10))

Each element now has its target extent, dimension, projection (use arguments target_dim, target_ext, target_crs above)

vapour:::imfun(a[[1]])

When we only specify extent it's not aligned to the source (but happens to be here because we chose aligned numbers).

x <- a[[1]]
vaster::x_res(attr(x, "dimension"), attr(x, "extent"))
[1] 0.25
vaster::y_res(attr(x, "dimension"), attr(x, "extent"))
[1] 0.25

If we say "_dsn" rather than "_data" we get a file name (or specify one)

 files <- sstfiles()
## these are fully expanded VRT chunks (but with GDAL 3.7 we'll replace with vrt:// syntax)
f <- files$vrt_dsn[1:10]
a <- lapply(f, vapour:::gdal_raster_dsn, target_ext  = c(100, 220, -60, -10))

TODO:

• the file target stuff needs to be able to add multiple bands to a single tif (or netcdf maybe)
• if only extent is provided we should align to source
• other cases, by argument "align" ?

[mdsumner]

this is now started for readsst() and sstfiles() in branch 'gdal-new-world' - it works for daily and monthly, but still a bit live in terms of working out various issues

[mdsumner]

there's now no special need for 'lon180', just give it what you want (we can't reproject with the raadtools functions, I'm not sure that's going to be a good idea - review once rolled out over other funs)