NKG: fix links to eur_nkg_nkgrf03vel_realigned.tif file (fixes #23)

[rouault]

No description provided.

[kbevers]

I guess this is the only way to sort this one out. It's a bit tricky that two files has now become one. There's no obvious way to add an alias like the one used below, right?

> echo 12 56 0 | cct +proj=vgridshift +grids=dvr90.gtx
 12.0000000000   56.0000000000      -36.5910           inf

>echo 12 56 0 | cct +proj=vgridshift +grids=dk_sdfe_dvr90.tif
 12.0000000000   56.0000000000      -36.5910           inf

[rouault]

There's no obvious way to add an alias like the one used below, right?

yes, that's a too tricky case for aliasing to work since you don't just need to change the grid name but replace +xy_grids=A +z_grids=B by +grids=C

Note: the examples at https://proj.org/operations/transformations/deformation.html should probably be updated to use the TIFF grid