Create infrastructure variation templates

**Summary**: Develop template system that automatically adjusts infrastructure configurations based on environment type, including resource SKUs, scaling parameters, and feature flags.

**Acceptance Criteria**:
- [ ] Environment-specific infrastructure template system
- [ ] Automatic SKU and sizing adjustments per environment type
- [ ] Feature flag system for environment-specific capabilities
- [ ] Resource configuration variation based on environment requirements
- [ ] Template inheritance and override mechanisms
- [ ] Integration with existing azd infrastructure provisioning