feat: Add PostgreSQL connection pooling support

- Implement connection pooling using `r2d2` and `r2d2_postgres`
- Add connection pool configuration options to `PostgresConfigBuilder`
- Introduce transaction functions with automatic commit/rollback
- Add functions for executing queries using the connection pool
- Add `QueryParams` struct for building parameterized queries
- Add tests for connection pooling and transaction functions

Cargo.toml

@@ -32,6 +32,8 @@ log = "0.4" # Logging facade
 rhai = { version = "1.12.0", features = ["sync"] } # Embedded scripting language
 rand = "0.8.5" # Random number generation
 clap = "2.33" # Command-line argument parsing
+r2d2 = "0.8.10"
+r2d2_postgres = "0.18.2"
 
 # Optional features for specific OS functionality
 [target.'cfg(unix)'.dependencies]