feat: implement database connection and configuration management

- Add database configuration with environment variable support
- Support both PostgreSQL and SQLite database drivers
- Implement connection pooling and timeout configuration
- Add automatic database migration system
- Include connection health checks and error handling
- Configure SSL mode and connection parameters
- Add utility functions for environment variable management

config/database.go

@@ -0,0 +1,26 @@
+package config
+
+import "git.secnex.io/secnex/certman/utils"
+
+// Config holds database configuration
+type Config struct {
+	Host     string
+	Port     string
+	User     string
+	Password string
+	DBName   string
+	SSLMode  string
+	Driver   string // "postgres" or "sqlite"
+}
+
+func GetConfig() *Config {
+	return &Config{
+		Host:     utils.GetEnv("DB_HOST", "localhost"),
+		Port:     utils.GetEnv("DB_PORT", "5432"),
+		User:     utils.GetEnv("DB_USER", "postgres"),
+		Password: utils.GetEnv("DB_PASSWORD", "password"),
+		DBName:   utils.GetEnv("DB_NAME", "certman"),
+		SSLMode:  utils.GetEnv("DB_SSLMODE", "disable"),
+		Driver:   utils.GetEnv("DB_DRIVER", "postgres"),
+	}
+}