Change GIS to plugin

[LINxiansheng]

Task Description

Change GIS to plugin

Solution Description

Move GIS functionality out of the seekdb core and into the standalone seekdb_gis.so plugin. Add a stable plugin SPI, core compatibility shims, plugin validation, and build tests so seekdb can run without built-in GIS dependencies

Passed Regressions

core test

Upgrade Compatibility

Other Information

Release Note

[CLAassistant]

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[LINxiansheng]

The mapping Dima issue is [delete GIS](