MDEV-34160: Implements ST_LongFromGeoHash

The GIS function ST_LongFromGeoHash takes in input a geohash and returns
its longitude.
The longitude is returned as a numeric value in the interval
[180, -180].
If the argument is NULL, the return value is NULL. If the argument is
invalid, an ER_GIS_INVALID_DATA is thrown.

Author: StefanoPetrilli <stefanop_1999@hotmail.it>
Co-authored-by: kevincheng2 <chengyf112@gmail.com>
Co-authored-by: Catalin Besleaga <catalin.besleaga@oracle.com>
Co-authored-by: Gleb Shchepa <gleb.shchepa@oracle.com>
Co-authored-by: Tatiana Azundris Nuernberg <tatjana.nuernberg@oracle.com>
Co-authored-by: Martin Hansson <martin.hansson@oracle.com>
Co-authored-by: Deepa Dixit <deepa.dixit@oracle.com>
Co-authored-by: Hans H Melby <hans.h.melby@oracle.com>
Co-authored-by: Jens Even Berg Blomsøy <jens.even.blomsoy@oracle.com>
Co-authored-by: Erlend Dahl <erlend.dahl@oracle.com>
Co-authored-by: Norvald H. Ryeng <norvald.ryeng@oracle.com>
Co-authored-by: BennyWang <benny.wang@oracle.com>
Co-authored-by: David.Zhao <david.zhao@oracle.com>
Co-authored-by: Erik Froseth <erik.froseth@oracle.com>

Author: 14 people