CRS instanciation from PROJ.4 string: set 'Unknown based on XXXX ellipsoid' datum name...

[rouault]

...when instanciating from known +a,+rf

and change WGS84 -> WGS 84 and GRS80 -> GRS 1980 to use EPSG names when building from +ellps=WGS84/GRS80 (fixes #3725)

Now we get

$ bin/projinfo  "+proj=geos +lon_0=0 +h=35786400 +ellps=WGS84 +units=m +sweep=y +no_defs +type=crs"
PROJ.4 string:
+proj=geos +lon_0=0 +h=35786400 +x_0=0 +y_0=0 +ellps=WGS84 +units=m +no_defs +type=crs

WKT2:2019 string:
PROJCRS["unknown",
    BASEGEOGCRS["unknown",
        DATUM["Unknown based on WGS 84 ellipsoid",
            ELLIPSOID["WGS 84",6378137,298.257223563,
                LENGTHUNIT["metre",1],
                ID["EPSG",7030]]],
        PRIMEM["Greenwich",0,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8901]]],
    CONVERSION["unknown",
        METHOD["Geostationary Satellite (Sweep Y)"],
        PARAMETER["Longitude of natural origin",0,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8802]],
        PARAMETER["Satellite Height",35786400,
            LENGTHUNIT["metre",1,
                ID["EPSG",9001]]],
        PARAMETER["False easting",0,
            LENGTHUNIT["metre",1],
            ID["EPSG",8806]],
        PARAMETER["False northing",0,
            LENGTHUNIT["metre",1],
            ID["EPSG",8807]]],
    CS[Cartesian,2],
        AXIS["(E)",east,
            ORDER[1],
            LENGTHUNIT["metre",1,
                ID["EPSG",9001]]],
        AXIS["(N)",north,
            ORDER[2],
            LENGTHUNIT["metre",1,
                ID["EPSG",9001]]]]

$ bin/projinfo  "+proj=geos +lon_0=0 +h=35786400 +a=6378137.0 +rf=298.257223563 +units=m +sweep=y +no_defs +type=crs"
PROJ.4 string:
+proj=geos +lon_0=0 +h=35786400 +x_0=0 +y_0=0 +ellps=WGS84 +units=m +no_defs +type=crs

WKT2:2019 string:
PROJCRS["unknown",
    BASEGEOGCRS["unknown",
        DATUM["Unknown based on WGS 84 ellipsoid",
            ELLIPSOID["WGS 84",6378137,298.257223563,
                LENGTHUNIT["metre",1,
                    ID["EPSG",9001]]]],
        PRIMEM["Greenwich",0,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8901]]],
    CONVERSION["unknown",
        METHOD["Geostationary Satellite (Sweep Y)"],
        PARAMETER["Longitude of natural origin",0,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8802]],
        PARAMETER["Satellite Height",35786400,
            LENGTHUNIT["metre",1,
                ID["EPSG",9001]]],
        PARAMETER["False easting",0,
            LENGTHUNIT["metre",1],
            ID["EPSG",8806]],
        PARAMETER["False northing",0,
            LENGTHUNIT["metre",1],
            ID["EPSG",8807]]],
    CS[Cartesian,2],
        AXIS["(E)",east,
            ORDER[1],
            LENGTHUNIT["metre",1,
                ID["EPSG",9001]]],
        AXIS["(N)",north,
            ORDER[2],
            LENGTHUNIT["metre",1,
                ID["EPSG",9001]]]]