community/xerces-c: move from testing and add to gdal
move xerces-c from testing and add to gdal
this enables the following GDAL drivers:
- NAS -vector- (rov): NAS - ALKIS
- Interlis 1 -vector- (rw+v): Interlis 1
- Interlis 2 -vector- (rw+v): Interlis 2
- GMLAS -vector- (rwv): Geography Markup Language (GML) driven by application schemas
no need to bump pkgrel of xerces-c or gdal, because ABI did not change.