- Add PaymentConfig with Stripe API key and webhook secret fields
- Add ChargingEngineConfig with base URL and timeout settings
- Add InfluxDBConfig with URL, token, org, and bucket fields
- Add MetricsPort field to ServerConfig for Prometheus metrics endpoint
- Set default values: MetricsPort 9090, ChargingEngine localhost:3001, InfluxDB localhost:8086
- Update Config struct to include Payment, ChargingEngine, and Infl
- Add Config struct with server, database, Redis, IMSI, and ES2+ settings
- Add ServerConfig with port and timeout settings (30s read/write)
- Add DatabaseConfig for PostgreSQL connection parameters
- Add RedisConfig for cache connection settings
- Add IMSIConfig with France MCC+MNC prefix (20893) and IMSI range
- Add ES2Config for eSIM provisioning with SMDP connection parameters
- Add LoadConfig function with default configuration values
- Include JSON
nutcas3