Create type-specific configuration file generation

**Summary**: Implement logic to generate environment-specific configuration files based on the selected environment type.

**Acceptance Criteria**:
- [ ] Automatic generation of type-specific ENV files (e.g., ..env)
- [ ] Automatic generation of type-specific JSON files (e.g., config.dev.json)
- [ ] Template system for type-specific configuration defaults
- [ ] Configuration file naming convention enforcement
- [ ] Integration with existing `azd init` and project setup workflows
- [ ] Support for both convention-based and explicit type configuration