TriangleMeshTriangleMeshDcdContact, add documentation

- Add documentation
- Use anonymous namespace
- Rename functions
- Update assertion failure message
TriangleMeshTriangleMeshDcdContact, refactor to use Geometry functions

- Move coplanarity test to Geometry
- Use isPointInsideTriangle test
TriangleMeshTriangleMeshDcdContact, modify depth and normal validation

- Use more generous upper bound