Allow SRID args in ST_Transform

[jesspav]

Currently, ST_Transform is only accepting utf8 args.
This change allows for SRIDs to be passed in as ints. It also adds some better argument checks.

Testing

Unit tests and manual tests.

Examples

> SELECT ST_Transform(ST_SetSrid(ST_GeomFromText('POINT (1 1)'), 4326), 3857) as geom;
┌─────────────────────────────────────────────┐
│                     geom                    │
│                   geometry                  │
╞═════════════════════════════════════════════╡
│ POINT(111319.49079327357 111325.1428663851) │
└─────────────────────────────────────────────┘

> SELECT ST_Transform(ST_SetSrid(ST_GeomFromText('POINT (1 1)'), 4326), 'EPSG:3857') as geom;
┌─────────────────────────────────────────────┐
│                     geom                    │
│                   geometry                  │
╞═════════════════════════════════════════════╡
│ POINT(111319.49079327357 111325.1428663851) │
└─────────────────────────────────────────────┘