Support GeoJSON related functions

[wey-gu]

Is your feature request related to a problem? Please describe.
To enable GEO from GeoJSON and as GeoJSON, this could be friendly to the application layer.

Describe the solution you'd like
Something like ST_GEOGFROMGEOJSON and ST_ASGEOJSON

Describe alternatives you've considered
n/a

Additional context
n/a

Thanks!