Dart 3 support, larger geometry model API changes and enhanced geospatial data format support.

This milestone tracks v2.0 for both geobase and geodata.

NOTE: the release 2.0.0 is targeted to the late 2025. For example JsonCodable and other macros as stable language features are waited before actually starting the version 2.0.0 planning and implementation (full macros not coming before "early 2025" but no promised timelines however).

Dart SDK requirement: Dart 3.4+ (records, patterns, extension types, etc.), starting for geobase and geodata releases 2.0.0. However 1.x versions of these packages continue to require Dart 2.17 (in pubspec.yaml it's specified as sdk: '>=2.17.0 <4.0.0'.

Alternatives for publishing new v2 packages:

• geobase and geodata packages with version number 2.0.0 based Dart 3 new features including macros
  • apps should decide whether use v1 or v2
• totally new packages geobase2 and geodata2 or named otherwise
  • this would allow apps depend both on v1 and v2 packages when transitioning