Version-specific GeoParquet Metadata Examples

[groldan]

This PR improves the GeoParquet specification examples by providing version-specific metadata examples that clearly
demonstrate the differences between GeoParquet 1.1.0 and 1.2.0-dev.

• Renamed the existing example_metadata.json to example_metadata_1.1.0.json for clarity
• Added a new example_metadata_1.2.0-dev.json that demonstrates features specific to the 1.2.0-dev version
• Updated all PROJJSON references to use v0.7 schema

Key Differences in 1.2.0-dev Example

The 1.2.0-dev example demonstrates several important capabilities:

1. 3D geometry support:

   • 3D bounding box with Z min/max values
   • Z dimension in covering specification
   • 3D CRS (WGS 84 height, CRS84h)
   • Z-aware geometry types (Polygon Z, MultiPolygon Z, Point Z)

2. Multiple geometry columns:

   • Primary column with full metadata
   • Secondary "points" column with simplified metadata and null CRS

3. Enhanced metadata:

   • Explicit "counterclockwise" orientation
   • "spherical" edges representation
   • Temporal dimension with epoch value (2022.5)
   • GeometryCollection type support

[cholmes]

Thanks for the contribution! Apologies for the slow response. I'll try to review within a couple weeks. Also feel free to come to our meeting to share / discuss, if you join https://groups.google.com/a/cloudnativegeo.org/g/geoparquet-community then you'll get the calendar invite. Every other monday at 11am pacific time.