GPKG: add a 'INDIRECT_SQLITE' dialect that goes through the VirtualOGR mechanism (e.g. for compat with older Spatialite)

git-svn-id: https://svn.osgeo.org/gdal/trunk@27817 f0d54148-0727-0410-94bb-9a71ac55c965
Merge branch 'trunk' into trunk_vc12