Database: register grid fr_ign_RGM04versRGM23.tif

added in PROJ-data per OSGeo/PROJ-data#132

Using Helmert transformation:
```
$ echo -12.82 45.16 0 | bin/cs2cs -d 8 RGM04 RGM23
-12.81999702	45.16000607 0.00000000
```

Using grid:
```
$ echo -12.82 45.16 0 | PROJ_DATA=data:/home/even/proj/PROJ-data/fr_ign bin/cs2cs -d 8 RGM04 RGM23
-12.81999723	45.16000619 0.00000000
```

Author: rouault

data/CMakeLists.txt

@@ -31,7 +31,7 @@ set(ALL_SQL_IN "${CMAKE_CURRENT_BINARY_DIR}/all.sql.in")
 set(PROJ_DB "${CMAKE_CURRENT_BINARY_DIR}/proj.db")
 include(sql_filelist.cmake)
 
-set(PROJ_DB_SQL_EXPECTED_MD5 "8145b5734f4007f81b188ac3b690e8b3")
+set(PROJ_DB_SQL_EXPECTED_MD5 "464b76e61daf9bced08669b735e51429")
 
 add_custom_command(
   OUTPUT ${PROJ_DB}

data/sql/grid_alternatives.sql

@@ -179,6 +179,7 @@ VALUES
 -- fr_ign - IGN France
 ('rgf93_ntf.gsb','fr_ign_ntf_r93.tif','ntf_r93.gsb','GTiff','hgridshift',1,NULL,'https://cdn.proj.org/fr_ign_ntf_r93.tif',1,1,NULL),
 ('gr3df97a.txt','fr_ign_gr3df97a.tif',NULL,'GTiff','geocentricoffset',0,NULL,'https://cdn.proj.org/fr_ign_gr3df97a.tif',1,1,NULL),
+('RGM04versRGM23.txt','fr_ign_RGM04versRGM23.tif',NULL,'GTiff','geocentricoffset',0,NULL,'https://cdn.proj.org/fr_ign_RGM04versRGM23.tif',1,1,NULL),
 -- Vertical grids
 ('RAC09.mnt','fr_ign_RAC09.tif','RAC09.gtx','GTiff','geoid_like',0,NULL,'https://cdn.proj.org/fr_ign_RAC09.tif',1,1,NULL),
 ('RAC23.mnt','fr_ign_RAC23.tif',NULL,'GTiff','geoid_like',0,NULL,'https://cdn.proj.org/fr_ign_RAC23.tif',1,1,NULL),